I’ve watched parts of most of these shows/universes.

Gotta say pacing issues abound in pretty much all of them in some form or fashion.

One Piece as a manga is probably the best on this list, but still has some pacing issues.

Gintama, as you mentioned, is also really great. But sort of requires some meta-knowledge of pre-2010 anime to really be elevated.

Unserious answer: Ghost Stories

Despite it’s flaws, I actually really like DBZ Kai as an alternative to the original run.

I’d agree with this. It feels like Shounen + the first anime a lot of millennials watched or really cut their teeth on.

Of specifically TV shows I think Evangelion, Dragon Ball Z, Full Metal Alchemist, Death Note, Attack on Titan, and Cowboy Bebop should be on this list.

Everything else could be purged. There is just a lot of overlap.

We should add some rom/com. I’d be partial to add Love is War.

At this point I would consider just waiting for when the series gets reanimated in The One Piece.

Or read the manga. I watched the first 150 or so episodes before the pacing issues really started showing up, then made the switch to print media.