Well, I dunno if or when a subscription model would be available, but if you have the hardware ready to go, you could go for the full lifetime license, it has a 30 refund period. So you could get it, try it, and if not for you after three weeks you can start the process to request a refund. Keep in mind however that depending on what you want to do there are still things that need to be set up and configured in the underlying TrueNAS system that HexOS is built on top of, but having said that most tasks you may want to accomplish that would need you to drop into that interface are either rather straightforward if you read all the options or if there is a guide already posted (for example setting up TailScale).
From the Terms of Service:
Any and all purchases are subject to a 30-day refund policy. To request a refund, email us at support@hexos.com using the email account associated with your purchase. For Early Access orders, the 30-days starts from the date you receive your invite to participate in the beta.