Is there a free trial available for the ARM64 SaaS plans?

Yes, Genymotion SaaS offers a free trial for arm64 plans. You must request it after creating and validating your account by clicking Request Trial in the top banner. See How do I activate my free trial?

If you choose Individual, the request is processed in up to 5 business days and includes 60 free minutes with 2 simultaneous devices. If you choose Company, it goes to sales, is processed in up to 2 business days, and includes 1000 free minutes with up to 10 simultaneous devices.