I get where you're coming from with that last physics update. I'm not skilled enough to say if it's more realistic than the previous tail happy physics or not but it's nowhere near as much fun as it used to be. Too numb and forgiving. One saving grace is a lot of the higher powered road cars are much easier to drive and road cars are my thing. Always a combo I haven't done and that keeps me coming back.
If you're always waiting for combos to come up that you like, I'm not surprised you're getting bored. I've lost count of the tracks and/or cars I've initially thought were crap but a lot of them soon grew on me after another look. Not Tsukuba though. Anything but Tsukuba.
Try mixing things up to see if you can find a bit of inspiration.
Are you using a physical copy or a download? I downloaded mine, never had a problem in game (stuck in pit/grid) and only ever had one disconnect from a daily race. Never deleted the cache on my standard PS4 either.
The more likely culprit is your console, game disk, hard drive or a bugged game install, not the game itself.