As for how to get from BCH to BTC... you'll need to send your BCH to an Exchange (Poloniex, BitMex, Binance etc)... and convert it to BTC and then send the coins to wherever you need. BUT... I would advise that you triple check the fees involved when using exchanges... a lot of them have fixed withdrawal fees which are simply ridiculous with today's value of BTC... (ie. 0.00050000 BTC withdrawal fees that's ~US$25!!?! )
Other options are the "instaswap" services like changelly and shapeshift etc... again, be wary of fees.
You can use FTX exchange.
FTX is KYC free, and you can withdrawal BTC for free. They cover miners fee and there is no withdrawal fee
https://help.ftx.com/hc/en-us/articles/360024479432-Fees
I have used their service and had no problems so far.