This game isn't that hard. Period. It can be frustrating to achieve goals like hideout req. and missions etc. but the general point of the game is easy as fuck to play.
I have a job, a partner who I live with, no kids, I work 8 hour days, 5 days a week on second shift. I can only do about 3 or 4 raids a night before exhaustion starts to affect my gameplay skill so I go to bed. I get most of my grinding done on my 2 off days, and that's if I don't have anything else to do.
I'm lvl 18, 50% survival rate and around 900k in the bank. Its not that hard to play this game bro. People get hung up on tasks and hideout upgrades, but those are just things to give you something to work towards. You don't have to do them.
Go into raid. Loot everything you find- everything. Search everything that isn't barricaded or nailed down, kill a couple of scavs if you see them. Avoid PMC contact if you don't want to fight, and I guarantee you will average 3 or 4k XP per raid. If you can squeeze out a mission in the process, then try it, but it shouldn't be your focus. Hideout items will literally come naturally with just playing like this. You don't even have to look for shit. File cabinets, computers, Toolboxes, duffel bags, dead scavs, and jager stashes will have everything you will ever need to build your early to mid-game hideout. I've spent entire raids in one building, cleaning it from top to bottom without ever having to encounter another player, scav, or even the rest of the map.
ONCE YOU HAVE ENOUGH MONEY TO FUND RAIDS COMFORTABLY (for me, that's 200 or 300k in the stash as low tier gear isn't that expensive) You can focus more on missions. Losing more money than you're gaining on raids? Revert to step 1. Loot everything.
For reference, I still haven't done my room 303 skier mission yet and im locked there till I find the key. But I'm still lvl 2 skier so his rep requirement wont be too important yet until level 20 something. I can spend this time banging out easier missions and looting.
If you're running on limited time to play the game, this is the way you should be playing it. (in my opinion) Otherwise you're gonna keep throwing yourself at customs to kill 5 scavs or get into room 206, die, lose money and gear, and discourage yourself from playing the game. There's easier ways to this shit, lol
TL;DR: Loot everything. Leave nothing. XP will come as you play raids. Missions aren't immediately important.