Ritzo use sumsub for KYC verification. I have never had an issue with any sumsub casinos. My passport was issued in the UK/Ireland. However this is not an option on the sumsub system.
I emailed my documents to Ritzo but they said I needed to provide my Irish passport. I sent them the law - https://www.citizensinformation.ie/en/government-in-ireland/ireland-and-the-uk/common-travel-area-between-ireland-and-the-uk/
The common travel act explains how this is not possible/nor required for someone born in the UK/Scotland or Wales.
The casino is still having a hard time understanding. Askgamblers meditating would help greatly as this could also be classed as a technical issue with their sumsub setup as well as ignorance with law.
I hope for help here