I have the BSC300 from IGPSport, which I think is the next down the lineup (bit further down in features, though), so I can maybe help with some of these doubts.
Routes must be sent/synced from the IGPSport app, you can either create the route in app (like said, from A to B) or sync from 3rd party. From what I checked you can connect with Strava and Komoot for routes, unfortunately
no RidewithGPS (at least currently). In the app you need to select which routes you want to sync, so it's manually synced not automatically.
It's also possible to import route files, so you can get a .gpx or some route file and import in app and then sync it to the unit, that's the workaround I've done to get routes from RideWithGPS, a bit more work but not much anyway.
Battery it's important to point out that the time advertised is normally a bit inflated, and also is 'pure gps use', like with no external sensors. So as soon as you add HR, speed, powermeter... the battery is drained faster.
My BSC300 is getting 10h+ with all the sensors, and the advertised is 20h, so I think for the IGS630 will still get a good battery life even with sensors.
Training at least in the BSC300 works really well, you can create the training session directly in the app (then sync it), and make the interval about HR or Power Zones, time-based or leave it open and pass it by pressing the lap button. There's a lot of options, honestly, I've been doing my indoor training directly in the unit linked with the smart trainer and it works like a charm.
It's also possible to sync with TrainingPeaks and import the training sessions.
About the BT connection and sync speed from app to unit, so far had no issues with it, if anything it impressed me how fast it is to sync activities, it's a major stepup from the other chinese brands I've tested, and faster than Bryton420 which I had before the BSC300
Do you mean the courses do not automatically get sent from komoot/strava/ridewithGPS etc?
Can you load power-based training programs?
I previously had a simple computer with speed/cadence/heart rate. I haven't tried the training programs, but you can upload them from the app to the unit. There's a brief pop-up screen, but it doesn't really bother me, because I always check if my sensors are synced (in case of dead battery) and I have to select the bike I'm using since I always rotate them.
All data downloading/uploading is done via bluetooth. Connection is stable as well. A 2 hour ride only sucks about 2-4% of battery life.
Doesn't seem to have Komoot integration. Right ?
Did you try it off-road, how's the quality of available tracks ? Karoo has them all in general.