So... what now?

[StriderShinryu]

If you're focused on the storyline, head into the Eden raid series and finish up the MSQ. That's really it. The MSQ is, well, the MSQ and the Eden series ties really well into sort of putting a nice cap on the story of ShB.

For storyline focused stuff on the side you can look into the extra 5.0 dungeons if you have time. You can also look into the Sorrow of Werlyt series as it fills in some perspectives from the Garlean side of things. This is all good, story focused stuff but is more supplemental content than "You need to do this now!" stuff.

If you find yourself with a lot of extra time you can consider going into Bozja and at least getting through the story there. It's more just background content with some nice lore and a decent story of it's own. It does have a bit of a deadline on it as it requires at least a small group of active people to actually complete it but, again, it's more side content and less "You need to do it!"

There are also the Nier raids but they really do exist as nearly a completely separate slice of content altogether. Plus, if you're okay with braving a possible long cue time later, you can always just hold off on them as there's extremely little chance that they'll connect to anything in the future (and if for some reason they do, bunches of other people will be pushing through them at that time too so you can just tag along in that rush).

As far as gearing is concerned, don't worry about it. As long as you have one class decently geared (and it sounds like you do), you'll be getting gear as good as or better than that from quest rewards and dungeon drops within a few hours of starting on Endwalker. Just make sure the main class you want to start the EndWalker MSQ with is capable and you're fine.

So, yeah, other than the MSQ and Eden, the only thing you really might want to put a rush on is the Bozja content since that will actually require other players to do (and most of those other players still doing the content will move on very quickly once EW drops).