Well, my experience in any online crypto casino, is the opposite of yours. I'm not saying that I always won or hit a big multiplier, but I also don't win only $10 every time that I use a free spin or a buying a bonus feature. The biggest hit that I recalled with a $0.20 bet was in Pragmatic games and it was around $256. I guess that either you need to change a game or probably focus on one and see how far you will go. Ofc you can try other providers like Hacksaw and NoLimits, but from my experience, both of them need more bankroll than Pragmatic to get something big.
Yes, it does have to be more capital to get free spins because if a little is deposited it feels less satisfied, but good wins in the Ducks Hunters game get a pretty decent multiplier, it's just that when moving to this pragmatic provider it is difficult to get good wins, maybe it's not the time to be lucky. Lol
But I myself for slot games only need capital from a $10 deposit so I only enjoy the game briefly.
Talking about the type of slot game in general, it really depends on our luck, I mean sometimes I can get free spins with just a small capital that I get from weekly bonuses which are usually very small (no more than $ 1) or it can also be said that I have gotten free spins several times with just a few random spins and that was luck, even the most surprising thing is that I once got a total of $ 60 with just $ 1.20 capital, that was very surprising.
But so far pragmatic is still the most wasteful provider to play, usually my balance runs out very quickly when playing there compared to playing at other providers such as PGsoft for example.
Regardless of whatever it is, the point is that slots really depend on our luck, so don't let us get carried away by emotions.