A used bike can be a good value, if you are confident in your ability to assess the condition of that bike, and what it might need. Typically, a 5-year-old midrange to higher end bike won’t need too much unless it’s either been abused or neglected.
Do you know, roughly, the different component groups/ levels?
As far as accessories and ‘upgrades’ go, are they the kind of things you would have added to your bike? Things like helmets, shoes and other ‘soft goods’ have almost no value if they’re not your size, and very little if they’re used. Also, some owners will try to add the full retail price of the accessories to the asking price of the bike. I don’t consider things like grips, saddles or tires to be ‘upgrades’ as these are wear items, and I might have a different preference for those things.

I might say that some updates may not offer noticeable advantages to a novice or a rider with casual aspirations.

Perhaps, but I would counter that everyone, especially casual cyclists, will benifit from faster, smoother, less problematic shifting even if they have nothing to compare the improvements to.

Still, I absolutely agree that there is nothing wrong with old tech in a soundly maintained bike. I’ve got a mid 80s Nishiki International that is a joy to ride! I’ve upgraded the brake pads and brake levers for better braking action, and changed Out the saddle because the original saddle gave up the ghost long ago. It is otherwise in the original configuration.

Cheers!

older used bike, take it to the shop if u need but it’s worth it.

2014 to 2019 is pretty close. Especially on the lower end. At least in my opinion. Of course when we are looking at a decade gap then it should be pretty noticeable to everyone.

Fairly common bikes such as the ones you referenced should be easily found at 50% off retail in the 4 year old range.
I suggest you definitely keep looking.