Just curious, what didnt sync for you?
Below are some initial thoughts on it:

I bought the CS500 for about $67. However, according to their website they're supposed to be releasing a CS600 soon. I think that one is color, which I'm not keen on myself

I checked with customer service and they do not currently sync directly with RWGPS, only Strava and Training Peaks. however they did say they would report it as a user request, so maybe one day if enough people ask for it!

So far, I've done about 15 short rides with it, and I'm pretty impressed. It connects to my sensors immediately. No GPS dropouts so far, I had that issues with using RWGPS on my phone every now and then. My power meter connected and it automatically knew it has it's own cadence detection without needed to pair it separately, which was confusing until I realized it was already there. It has an auto wakeup thing which is nice, still getting used to that. Contrast on a sunny day is good, unlike what i read in the reviews. Came with a screen protector (like people use on cell phones) which was unexpected and nice. I dont trust the rubber band mounting they provided, It'll probably last a couple years, but I opted to buy an aluminum fixed mount.

Now as far getting the rides logged online: From what I can tell, it requires a connection with the phone via their app. Their app does ask to run in in the background nearly every time, which i haven't opted to do yet because I'm not full back into daily riding due to injury. Due to this, in order to get the rides from the device I have to go into the app while the device is active and connected and it'll sync with my phone, at this time it immediately syncs to Strava. Like the moment it shows up on the COOSPO app screen, I get a Stava notification. So If you use Strava, and run this in the background, it's probably just happens as soon as you finish your ride (permitting you have cell/wifi access). To get it to RWGPS, I use Tapiriik to sync from Strava to RWGPS. My initial fear with using Strava as the initial data source was that my HR, Power and Cadence data would be paywalled, because back in the day when I was doing this more frequently, that was the case. Now it seems data uploaded to Strava also exports 1:1. Testing this manually, you can export to a file from Strava and upload to RWGPS and still retain all data. Same goes for Tapiriik syncs. I just got my sync to RWGPS this morning and found all my data there. Strava seems to only paywall the analysis of the data.

As far as naming goes, in RWGPS, it auto-named my 4 rides yesterday as "Morning Ride" "Afternoon Ride", "Afternoon Ride", "Afternoon Ride". It did tag my bike in RWGPS and Strava, but I only have 1, so people with multiple bikes may have to deal with that differently.

One minor annoyance I have found, but just need to learn to adapt to is: Even if you save a ride, you have to back out of that screen otherwise it wont sync it. I've had to go back to the bike a couple times to do that. Not huge issue, but something to learn to do additionally.

Now I need to figure out route planning to see how that works. So far though, I'd say totally worth it for the price.