I'm not too familiar with your diagram, but levels 3 and 7 would both seem to apply to how consensus is maintained here.
My diagram is of the Open Standards Interconnection model - something anyone working on networks learns right away. Using words to make you sound more intelligent usually has the opposite effect. :/
Anyway, if anyone is still interested in you, you never answered how you "
always maintain the private keys to your bets and never send coins to a trusted intermediary".
Check Degens.com which is a non custodial sports betting exchange that's been around since 2017. We utilize ethereum smart contracts.