Post game advice needed

Playing non seasonal wizard lvl 70 paragon lvl 50 (not making a new character) so no free 6 piece set (haven't played since 2012 and rebought the game like a week ago)

Just finished the campaign yesterday

I have no idea how I should start the end game or how I should go about getting better gear or getting a full set without it just being handed to me

I'm able to do like T1 T2 bounties without issues just not fast. It isn't fast enough for my liking so I would want to lower difficulty but then I don't get the "new legendary items at 70" or whatever it says when selecting difficulty

D2R I can get enigma hoto cta in a week farming LK and go do uber trist uber ancients without any issue but for some reason I can't figure out D3. The game has such high density everywhere you go and areas constantly branch off into useless exploration all the time. I really hope that when I start D4 for the first time when the expansion comes out that it's much better than D3 and way less "hard" or confusing

The campaign was fun after all this time but this post game doesn't seem like it's for me but I still want to experience it all. I don't care about doing GR150 or whatever but I would at least want to something reasonable