Subscription is a big nope here, though. Especially for Mac software, I'd expect something where you pay for one major version, that is guaranteed to works on specific macOS versions, and gets minor bugfix updates too. But maybe the next macOS version requires a newer major version update to run, in which case you pay an upgrade fee to buy the next major version - or maybe the next major version has new features you might want to upgrade to as well.
My old Macs are stuck on 10.13, and I see Ubar mentioned elsewhere in this thread and that it's still compatible with 10.13. I might consider the $30 one off price to buy Ubar and keep it forever, but I wouldn't do a $10 subscription.