Simple, if you're worried about KYC, just gamble with small amount money and don't join any promotion or free money/spin, the casino wouldn't ask you to submit KYC since your account have normal activities.
It's true to read rules of events like free spins before joining it. If you see rules are not attractively good enough or contains some requirements you don't like because you see it violates your privacy, simply ignore those events.
Not completely true in general because I've experienced myself (not in Duelbits) where I played normally with small amount, did not take any bonuses/promotions but the casino ask me to do KYC on my 1st withdrawal request worth no more than $200. That's not the point though, taking bonus/promotion is fine as long as we do not try to abuse it. In most cases, many small players were asked to do KYC because their accounts are suspected for abusing the bonuses.