However, I'd like to know if there will be BTC miners once the supply is fully mined, and will the fees for sending from wallets to exchanges be high?
Your thoughts on this literary amazed me. Well basically the time frame is so much ahead that didn't even crossed this on my mind. Well for your question, miner's won't stop. Cause if they do so who will confirm the block. Rn miner's are getting paid by both mining the bitcoin and by taking the subsidy fees for every txn. So yes there's a chance that fee's might rise higher.
Some folks are saying that let alone txn fee won't be enough for miner's. Well we won't never know what will happened after another decade. Our technology is improving speed of light. I belive we will be advance enough in mining tech that it will be cost effeciency.
I think it will be enough, but this question would not stop being asked simply because of its scale and importance, yet we won't be able to see how it turns out..