buchla is still making synths, although they are very idiosyncratic as always. here’s a recent unit–
https://buchla.com/easel-command-and-208c/
top quality digital fm synths did have envelopes the end-user could adjust. filters weren’t required because fm synthesis is an additive process, not subtractive, and sonic design was possible from the yamaha dx line onward.
as i mentioned above, the first synthesizer i had a chance to work with was a roland system 100m in college. i’m well acquainted with the “limitations” of analog synths but i’m also acquainted with their profound ability to design sounds. you should have a look at the demo video for the moog grandmother i linked to above.
