Well I would love to but I have to do the bridge for BAY which will eat a lot of my time. Thats a more complex bridge because of the peg. The theory is similar though. However after I finish I can show you how I did it. It's never really perfectly trustless because at the end of the day you need lots of validators on ETH side to mint coins based on BLK chain. Also you need to decide how the governance is structured... on BLK side you can have the stakers check ETH chain and then a sort of mint or burn type system. The part where governance is needed is on ETH side so you could choose the top stakers and give them ability to sign off on mint but it's really a critical question because you also don't want them all agreeing to mint BLK out of nowhere lol.

The "trustless" way to do it is have a group post a bond or something that can get slashed if posted chain hash data is false (similar to a rollup) but that's too much work for the time being (not to mention cost of ETH TX fees) and really a multisig with trusted nodes is a faster way to get the job done. Still, who pays the ETH fees to hop on to the bridge? Users? Maybe better off on other bridged networks until fees drop.

I have an airdrop chainz scanning tool that scans the rich list, pulls out public keys and generates equivalent ETH addresses using same public key without even needing to inform the user about it so that makes for really fast setup for governance (you can do a sort of merkle tree airdrop for the allocation of governance based on BLK stake weight).

Anyways, I don't check this thread often however check in with me later in the year and it's possible I will have the BAY bridge done and you can copy it's mechanics(of course  minus the peg parts because BLK doesn't have a peg).

One advantage to being on ETH or BSC is you can use their smart contracts and also free listings on AMM exchanges like Pancake or Uniswap. Of course thats not totally free because you need to put up liquidity.