I don’t want to renew my ISA in the new tax year - will I have to continue to pay for my current ISA?

Yes. As you will still have a Freetrade stocks & shares ISA, it will require management and reporting. If you don’t want to continue to pay for your ISA you’ll need to sell down your positions and either transfer your funds to your General Investment Account (GIA) or withdraw them in order to close your ISA.