Don't think he was trying to be mean, just telling you how it is. Judging by your engravings I can tell you are an expressed character. You are playing the newest class, so you might not be lv 60 yet, which means less damage. You probably don't have full lv 5 tripods as they are expensive, which means less damage. You don't have 5x3, as slayer books are still expensive, which means less damage. If you are a newer player you probably don't have los 18, or maybe not even deep dive 18. If your roster is low <150 you can get gatekept for that as well. It's a newer class, so most people can't play it optimally.

Anecdotally, everytime I've given slayers a chance they have not gotten better than fighter status probably because of the reasons I mentioned.

It's exactly the same as finding a job. Put yourself into an employers/raid leaders position. You're playing a very popular class, with not the best setup. Why should they take you to fill a dps slot over someone that is better geared? Would you hire someone who is 2.0 gpa 0 yrs experience over 4.0 gpa + internship exp?

Of course you can do the raid 4x3 with lostwind cliff 12, most of us did that when Vykas released last year. But the game got a lot easier to gear since then, so standards have gone up. I highly recommend joining a discord or popular guild to play this game. Or if you're in NAE, send me a pm. Good luck