I can't find any info on that. I mean just finishing main campaign + all/most sidemissions on standard difficulty, not maxing everything out. Should I expect like 20 hours or 50 or more.

I would expect 20 to 30 hours of play time. This depends on how much side mission you want to do.

Ah, that's cool. I just realized the side missions are randomly generated but I feel like they quickly become rather boring so I guess I'll keep grinding at minimum just to level up a little for main quests.

So don't use the hack pads, as hacking is far more boring (I don't use this new 'feature').
I think this game is not for you: side missions are necessary to grind your factions, and factions story is what is the more interesting in this game.

I don't hack at all, realized it's pointless after second mission or so. I still wouldn't say it's overly interesting. Dungeons all look the same, there's enemy in every room, and types of enemies are very few.

I think I'm about the end of campaign (my current mission recommends level 27 and I read somewhere that level cap on NG is 30) and I do side missions mostly for loot which is pretty good at the moment (epics from minibosses). What factions story are you talking about? So far I haven't encountered any story besides main questline and involved corps.

There are side quests involving other corps, if faction status is enough high. Yes, often to increase status means greatly decrease with other, so we have to choose and be carefull, as doing anything and all decrease status with everyone.

So something like killing those Paladins group for Dablue Yutaki yes? I didn't pay much attention on these corporations because farming reputation seems very time consuming and from what I found the rewards aren't all that great. On top of that I just finished the game and I see that in NG+ all reps are zeroed.

Yes, roleplaying the more is long (50h the game), but I find it the more fun, even the rewards are not great.