If you’re in Orlando, closest freshwater options will be Alexander (shallow), Blue Springs in Orange City (closed to water activities right now I think), and Paradise (AOW required).
If you’re willing to drive a little further, Blue Grotto, Devil’s Den, and Ginnie are all privately owned, popular, and offer on-site gear rentals and fills.
Personally, I like the state parks - Manatee and Fanning both sometimes have manatees, and Orange Grove has been nice lately. Buford is gorgeous but more advanced due to depth (165’) and overhead environment. Troy and Royal have been browned out lately, but good options when they aren’t. Rainbow River is a fun drift. If you’re cavern or cave, that options up a few additional options.
My personal favs for open water are probably Buford, Ginnie, Blue Springs, Paradise, and Royal/Orange Grove (in that order). I’m also very fond of the swim-throughs at Devil’s Den. Blue Grotto has cracked down on the deep portion lately, and has gotten extremely overpriced for what it is, esp when overcrowded with open water classes that demolish the vis.
Nearly all the springs (except Royal and Alexander) require you show up with a buddy; you can usually
arrange a guide in advance if you aren’t traveling with someone or can’t find someone local to buddy up with.
There’s a
nice map here, if you’re trying to figure out something not too far away. Have fun!!!