When it comes to sportsbooks and poker, fiat casinos are better, simply they offer a lot more, higher limits, more games/markets, crazy promotions... to not mention people who bet with higher amounts and what kind of problems they had with some crypto bookies (you could see that here on the forum). Don't get me wrong, I am all in crypto, I don't use play in any fiat casino, but facts are facts!
I guess Stake and Sportsbet are the biggest and most popular in crypto, after all both are sponsors of English clubs! But I rarely bet there, mostly I am on Gamdom, BC, Betfury, Wolf... it's where I play other games and I always have some money for some sports bet! I don't have any complains, they are great for now, but I guess they lack some of promotions others have!
You mentioned several gambling sites and a few of them are big sites. If you cant see the promotion that you want on one site then you should find it on the other but what is that promotion anyway that you are looking for? Is that promotion can only be found on bet365?
But, that could be normal because it was a fiat site while the only ones that we have here are crypto based but when it comes to limits or betting with higher amounts, we have several crypto sites that offers it, stake and sportsbet are two of those but I don't know about the others though you might need to comply to KYC since your dealing with bigger amounts.