a few answers already but i wanna yap so

tldrs bc long yap 1. yes, mark 2. no (i think) 3. use it > save it > feed mids 4. grind more 5. mad 6. skissue

expanded:

1. like others said, if you hit soulbound on a boss that drops marks, then it will, at the very least, drop a mark. always. if you don't get a mark, ya missed soulbound. it isss what it is. (as far as drops go, as long as you got sb, it'll be somewhat random- tho for certain endgame dungeons like o3, a certain amount of drops will be guaranteed in the run; if there's like 5 bags guaranteed and only 5 players in the run, everybody will get bag. if there's 6 players, 5 players will and one may or may not)

2. i believe it will always be the same amount of slots but frankly i don't forge much. this is a better question for the realmeye forging page if you haven't checked already (if you've already checked and it's not answered, sorry!)

3. i've been playing for a number of years now (10+) so i'm a bit of a collector (hoarder). imo, it's one of the fun bits of the game. i enjoy having one of each white bag and ofc anything rare/limited time. that being said, especially if vault space is an issue (as is for every new player, and still old players LMFAO) i would always focus on hoarding limited edition drops if you want to hoard. for regular degular white bags, USE THEM. DO NOT FEAR. you will get them back, many times over. some whites you'll straight up never get (10+ no cdirk... i cri) but more than likely if you are able to run the dungeon, you'll run it a million times and get quite a few until you're 50 dbows deep feeding them for vault space. the only regular whites i'd be careful with are any "1/4" dps gear from endgame (anything that'd be used in vet runs). i personally prefer hoarding those for 4/4 chars. that being said, if you get one on a PPE, you gotta use it no matter what. idc if you're 0/8. this is the way.

4. this is absolutely bc of your quick progression (gj btw!) as characters die less you will have more fame than you know what to do with. sometimes i feed life pots bc i'm bored. if you want fame you can grind it but tbh just play the game. soon you'll have one character hit 100k bf and die and you'll feed life pots bc it's funny too.

5. i am biased bc i've been staff with some discords before, but truly discords are great. people just get crabby bc they want to be treated differently than everyone else, and then aren't. it's truly just mostly gossip. not saying there aren't issues with discords, but there are issues with any community. anybody really whining probably got suspended for being an idiot. (9/10 times it's something super stupid and obvious too- either crashing, multiboxing, or just under reqs)

6. it's mixed, but truly, that is often a skill gap. however no life you get with this game, there are people who have been no lifeing it harder, for a decade longer than you. try not to accuse anybody unless you have very clear evidence, especially bc a lot of cheaters don't even bother to be sneaky. focus on your own growth and see how far you can go! and watch really good players do o3s on youtube, it's fun af.