I was like you a couple of years ago. Wanted to get into vinyl again but had no idea. Back in the day I just put a record on and dropped the needle! Never knew there was so much to learn. Still don't know much about the specs, numbers, etc. but learning. I picked up a mint used Rega Planar 6 and purchased a new Rega Exact cart. Setup was super easy. No spacers needed with the Rega cart. It sounds great with any phono stage I've used. Currently a Musical Surroundings Phonomena 2+ with gain set at 40dB and input loading at 47k. Considering trying an Ania mc cart in the future but no rush.
It's great that you are doing the research - kudos. But, you might want to start simple with a Rega cart for the Rega TT. Pretty much plug and play.