I have noticed a hang time on the new tech selection screen also, generally lasting a few minutes by mid game. I don't recall this happening in pre 2.2x versions. 

You might be on to it, it feels longer when there are more players. 

I also noticed the splash screen on startup (galciv4/supernova) pauses for awhile now before starting the video.

It is starting to remind me, of how I would wait about 20 minutes for Close Assault, a ~32k-48k game to load from cassette tape in the early 1980's. Or the wait while Ultima II requested a 360k 5.25 floppy disk change and several long minutes load time because you moved to a different area of the map. How dare Stardock make me wait a couple minutes while the game setup happens . 

Amazing, that's basically the same setup I have.  The only difference is I have an I7-7700 running @4.2 GHz.  But we both have 4 cores and that's important because they game is multithreaded and will needs at least 4 cores to run smoothly.  The GTX1080 may be old but it's still a very good video card.  Like I said I do see a small lag (10-30 sec) when picking new research, but nothing like you are.  Just as an experiment try playing huge map with only 8 AI civs and see what happens.  No idea why a small map with only 4 ships should have issues, but I've never played that type of setting.