OK, you need to measure the chainline precisely. It needs to be 45mm for a road setup. You have to choose a BB spindle that gives you that 45mm chain line. Read here:
https://www.sheldonbrown.com/chainline.html
BTW- are you greasing the square taper? It needs to be dry when you put the cranks on the square taper spindle.

I previously had a 122.5mm bb on this bike which I bought before I figured out about chainline. It's probably fine with this original 117mm now that I look at it.

If you get a Shimano Hollowtech crankset in the genre of your bike, MTB or Road Bike, And stay with a crank made for the speeds on the rear, then you likely won't have to worry about chain line. Or much of anything else since it appears your bike is BSA threaded. Hybrids probably will need a MTB crank.

With the 122.5mm bb the chain was almost falling off the middle chainring with the rear big cog. It's way better with the 117mm, little noisy on the big cogs, but also on the smallest rear cog it's also now at a bit of an angle. Not sure if this ideal or not, but far less concerning now. I kinda got tunnel vision dealing with the cranks on this and my other bike I only now checked it with this bb installed. I can test ride with this current chainring offset and see if I wanna change it.

That means you have a triple.
Put it on the middle ring and a middle cog.
Easy if you have an odd number. If not try both middle cogs & compare the difference.

NOW- Stand a way back, behind the bicycle and eyeball it,
It's pretty easy to see if the chain line is parallel to the center line of the bike.

Also a bit off topic but is this within spec for a new shimano chain with these kinds of gaps? It's rubbing against the cage of my RD and adjacent cassette cogs too and the shifting is kinda rough. Did my LBS sell me a fake chain or something?

There is 8 cogs, by eye 3rd of the small cogs lines up with the middle chainring. The middle of the cassette lines up with the small chainring instead.

Middle ring should look "equally off" of parallel on cogs 4 & 5. (at least you can count from either end)

the center between the 4th and 5th cog lines up with the smallest front chainring. The chain sits straight only on the 3rd rear cog with the middle chainring. It's not hard to see it's offset otwards.

I've had several bikes with double chainrings but never triple. Every single one of them had the same BB, I think it was 109.5 or something like that. This is exclusively on Octalink V2. I've never had V1.

They were great. Stiff, reliable, simple, self extracting. Back in the day, I took them off the bike all the time. For cleaning or changing chainrings, or just because I could. I might be wrong but I really think they held up a lot better to repeated installation.

I say that but if you've ever had a crank with outboard bearing cups lake every modern crank from every modern brand, those are even better and hold up to repeated installation basically forever.

None of this should matter though. Unless the bike lives in a lab or something where the configuration is constantly being changed, a handful of uninstalls and reinstalls won't cause appreciable damage to anything. Including square taper.

Well, I was going by eyeball. FWIW, my V1 is in a 3 x 9 drivetrain.

109.5mm length Octalink was probably V1, used on doubles by Shimano and the very few other brands that used Octalink.

IIRC V2 didn't have any lengths shorter than 113mm. The few Shimano road double cranks that took the V2, used the 113mm length.

The Octalink interface is quite durable if installed properly.

It can be difficult to decern between the version if just eyeballing. Many people have mistakenly tried to use the wrong version.

It was also confusing since Shimano used both versions across road & MTB lines. Other manufacturers also did some 'crossing'.

Does octalink need to be tightened again and again after install as you ride it at first? Like with square taper?

Square taper shouldn't need retightening, it sounds like you didn't torque it adequately, or the crank was faulty.

What would you guys say about this square taper? Does this look overtorqued?, cause I can see a lip at the end of the square hole. And this is about what I see with every used square taper crank I can find.

I've seen this recommendation many times now and even someone say to check the torque on the cranks even once a week. I was dealing with already mistreated cranks most likely. The only cranks I did not have any issues with riding them for a long time were steel.

These were the original cranks. And I definitely over-torqued them by a longshot. Is this still usable? Or is it just gonna keep getting worse no matter how I install them further?

So V1 or V2, no idea what I have I guess. All I know is that they always fit and worked well. Too bad they became yet another abandoned standard. That's your biggest concern with Octalink.

I've never had issues with square taper coming loose. I know you can stretch them out eventually if you're hamfisted. I do question the judgement of someone who chooses a screen name of copper thiever.

Not in my experience. I've had my crank off several times, and each time I torque it to spec and it doesn't get loose.
FWIW, I have the same experience with square taper. I grease the taper and the threads on the bolt.
The interface I *used* to have trouble with is the cottered crank. I would repeatedly re-tighten the cotters. Until I got a Cotter Pin Press... now it's "one-and-done".

With cottered I found I could file around the cotter pin and then break off a piece of hacksaw blade to fit in-between the spindle and the cotter pin and rode the heck out of it with no issues.

I also installed steel cranks on another old bike and no issues with that either.

my last 3 bikes were such that I haven't used a bike lock for years now. Rode them for years for virtually no cost, finding salvaged parts as needed. Something like an over torqued crank never even slipped my mind until just recently. I'm glad that I got to witness a couple trash bin cranks fail on me before I got my hands on something a little more costly.

If your chain is rubbing the cage on the FD with a 8 speed rear. That does suggest something is wrong. But unlikely the chain. Just glancing back quickly through all the threads, I have to wonder if you have a bicycle that has a mishmash of different components on it. And is no longer anything like it came out of the door of the shop when new.

A incorrect chain line can be one reason. And the wrong FD for the current configuration of the bicycle another. As might just be a simple adjustment of the FD.

For goodness sake can you :
1. get out a ruler to measure the chainline
2. beg borrow or steal a torque wrench so you don't keep wrecking whatever crankset you are working on.

Sorry man this thread went way off topic. I sure will get a torque wrench for installing any more cranksets. The chainline is 46mm front and 44.5mm rear