I still don't your bonus terms but since you are promising a KYC free casino at all times. Why not make the bonus requirements more tighten to prevent abusers and fair at the same time for normal players?
When a casino offers a lucrative bonus promo, there will be abusers all the time as long as they will have a motive. Betcrypto had a 200% bonus for the first deposit and 100% on reload. Abusers took advantage of NO KYC and created multiple accounts. As long as you have such a lucrative bonus on welcome, no one will go for the reload bonus now. They will only look for the 200%. Since betcrypto is a NO KYC casino, there's not a lot of options to detect multi.