can you actually game casino bonus systems successfully

I keep seeing people talk about clearing deposit bonuses or free spins for a “guaranteed” edge, but I’m struggling to see if you can actually get ahead with these promos. I’ve tried running through some WRs on slots and a few times it’s gone ok, but just as often I wind up busting before I can cash anything out. Maybe I’m picking the wrong games or not playing it smart enough? I’m not scared of terms or fine print, but some of these bonus T&Cs feel like they’re written by people who want you to fail.

Anyone here got a method for working these in your favor, or is it just wishful thinking? Would love to know if it’s actually doable, or if the house really always wins, even with the “free” stuff.