The ability to host your own data - both for privacy, and insurance that the instance you host your account in won’t suddenly disappear.

Excalibur Prime so I can watch the world burn.

Regarding number one - If you’re coming back from a long time away and haven’t done any quests at all, then I recommend doing quests. They unlock important content, and there’s a few that are necessary to be able to do Eidolons properly.

As for the remainder of the questions, if you care about meta (or at least some form of guide on making weapons work) and the performance of weapons/frames then I recommend you check out the tier lists and build guides on Overframe. Not all super upvoted builds are up to date or great, so I recommend you look around on each piece of equipment, read the comments on the builds, and scrutinize for yourself on what you think might work and be good.

Good insight! (Also, nice to see you here!)

How do you feel about Operator/Drifter? There’s something to be said about exploiting the one thing you always have direct control of, being your operator loadout, in a mode where success can have RNG as a heavy factor. Especially with nice CC options like Magus Lockdown.