Finding a guild helps, I joined EVOS who runs Triple Trouble each day after reset around Midnight EST. They are a great group and helps when you want to find people to do content. Also simply posting in LFG is shockingly effective. Its really one of those "build it and they will come" type of deals. The community (in my experience after playing for a few years now) is that many people are willing to group up, just not everyone is willing to START the group.

Also, I have found lots of repeatable fun in different map metas that very organically allow you to group up with people. Besides that, if youre feeling solo play, there are tons of great collections to work on that have genuinely worthwhile rewards (herta, princess, Ley matter converter, griffon, ascended banners backpack from PoF, etc.).