We had this problems a lot. You have to make it painful enough that scammers do not want to bother.

Put Cloudflare in front of your IP. Everytime someone abuses you then block their IP at CF. If you can automate this even better.

Reduce the service for a free trial in someway that hurts hackers but not real customers. You will have to think about this it might tricky or not possible.

Add software to your stack to watch for port scans and cut the users off instantly. Or watch for DDOS. There is some number of packets that come out of a valid session vs the number that comes out of DDOS.

And then finally the trials that abuse you are junk trials they will never convert. The CC definitely will keep your trials low it just will I have seen that first hand but your conversion rate will be through the roof.