I believe I read that to spend it I would have to send it to a hot wallet
Either cold or hot wallet, you can send your bitcoin to other people, addresses. If with cold wallet, you can not send your bitcoin, it sucks and nobody use cold wallet.
Your question reveals something wrong in your understanding too. If you can send your bitcoin to a hot wallet, you can send it to any receiver. It's an on chain transaction and it's spending.
and then send what I want to spend to that person and then the remaining balance back to myself at a newly generated Trezor address.
If there is leftover of your bitcoin from UTXOs you choose for a transaction, you will receive it in a same address or in a change address. Change address is recommended because it helps your privacy and anonymity a little bit.