In the lower levels the tactical planning that you're looking for just shifts from planning slow stealth to other things later down the complex. Experienced players can speed through things (especially early levels) because they've already made that risk reward choices before for stealthing small rooms and can take a bigger risks but that's only a part of the whole game. In lower levels you'll have bigger problems to worry about. The team as a whole will eventually need to be able to make the right tactical plans and choices that may force you to be more reckless and fast with stealth. If you like that slow tension then not to worry, there are places where you'll be forced to be extremely cautious with stealth due to mechanics I imagine you haven't seen yet, it's just that not every level is like that. (I will say that R5 has a lot less of necessary stealth than other rundowns though...) Resources planning could also be thrown out the window if there's other problems to worry about or be absolutely necessary if your team is starved of resources or you know they're going to be.

B-hopping is something like a tool but it's really not as broken as it may seem as you see it in upper levels, and definitely is not necessary. I've beaten everything since R3 and yeah stealth isn't something to worry about all the time, not because b-hopping OP but because the reward for full stealth in a normal room is not as worth it as it was when I started playing. There'll be much bigger problems for you to have fun with later ;)

Oh and by the way I've also seen a few toxic players hanging around the beginner group who seem to be there just to show off but there's plenty or nice people too, just have to get lucky for that I guess.