Potential returner with some questions.

Old hat that quit shortly after the first tier of BFA. Played prot war vanilla through ICC, resto shaman all through Cata and MoP, bear through WoD, vengeance until antorus where i played holyP until the end of uldir when i quit. Came back for about a month during the first tier of shadowlands. Been randomly missing the game and debating coming back but would like some clarification from current players on a few things before i comit the time/money.

1. One of the reasons i stopped playing was the weekly required hours outside raid. Im not looking to run mythic again, likely stick to heroic and call that good enough as Between school and parenting i dont have the ability to dump 3-5 hours daily anymore. Is M+ still basically a requirement to keep up to date in raiding? Am i going to fall woefully behind if i just log on for raid some weeks due to real life commitments?

2. Alts. I'm struggling to decide between Holy priest, Vengeance/Fury DH, and Bear. I've heard they made alts a lot less tedious to manage via warbands, but how viable is this to maintain 2-3 characters now?

Mostly i want to know how likely ill be able to run heroic raids, as raiding is what i play MMOs for. I can commit to specific evenings for raiding no problem, my issue is theres going to be some nights outside of raid i just won't be able to play (or ill want to just do something else) and I'm curious just how viable raid logging is in todays environment? God it's wierd to think i havent actively played the game in like... however long ago Uldir was.