Sidenote, i value FOSS but i'm supportive of your desire to keep it closed and make money.

With that said, i'd never pay $5/m these days for something unless is had very good value to me and obvious ongoing costs i'm using (servers/etc) for the dev/company. Those costs would need to be clear though, not just "we chose to run some servers so that we'd have features which justified subscriptions"

I would however, pay for upgrades - ie the licensing model employed by JetBrains/etc. Which can come out to $5/m (or yearly purchases, etc), or w/e, but most importantly the software keeps working if you decide to cancel.

edit: Also i'm on Linux. Looks like i can't buy it anyway haha