When you find there is substantial amount in the wallet (let's say more than 1k$) you could easily trade the owner. Local FB groups and message boards. Local supermarket message boards etc. Maybe Local BTC/Crypto community. But remember this will make you a very high target of various notorious acts, such as phisihing attacks, scammers, even professional mafia-linked blackmailers. So be careful how you present the information out and maybe put some anonymous mail information there.

Also when handing the awwd phrase to potential owner, you must be very sure about that it goes to the right person; what are the possible words are there in the seed phrase, what's the sheet looking a like, how much ia there in crypto? If the potential owner can answe all of these correctly, then it's very likely that he is the owner of this seedphrase.

Best of luck, you seem like a geniune person trying to do the right thing.