The cult of the new is pretty strong in modded Minecraft. To be honest, I haven't done much modded stuff in awhile, but 1.16.5 is a solid choice or at least was back when I last put a pack together.

Create is the big new mod that has everyone buzzing. In some ways it's a reaction to the RF-ification and magic blocks/multiblocks that dominated the 1.12 era. Everything is very nice and modular, and it reminds me of Rotarycraft in that respect, though they are very different mods.

Dang it, now I want to play some Rotarycraft. Reika has enough 1.7.10 mods that you can essentially put together your own pack of just them, but I digress.

I feel that most people play modpacks nowadays, but maybe I'm biased as a packdev. I've seen some good progression packs come out, if that's your thing. I'm biased towards my pack, Brass, of course, but Create: Above and Beyond is the official Create modpack with loads of custom content. I never got around to playing it, but it looks neat.