1. Flatwounds do emphasize the mwaah a little less than rounds, but the difference isn’t huge unless your flats are dead as can be. Bright flats also help a lot.
2. Not necessarily, Ibby basses are generally good even the cheap ones.
You can choose to not look at the lines, so blah blah to the unlined is easier comment.
I would advise you to start with practicing the intonation, never mind the vibrato. Also switch off the chorus. Remember that the more meaty the finger the more to the middle of your finger the fretline will need to be to be in tune and your pinkie will likely be sharp if you do the same (more boney).
Once intonation is back in shape start giving it more feel with both right and left hand.
Also you get more mwaah when you play closer to the neck, heck I often anchor my thumb on the neck....!
stop worrying and only play fretless for a bit, you will soon get back into it.