@Ruprecht, I have been operating proxmox for 10 years without a subscription. Still using it today and I'm gonna buy the small business subscription for one of our work servers running proxmox.
No, you don't have to buy it! You can stay on the free version, like I and a lot of people over the world do. If you run into trouble, normally
the community here or in reddit will help. That's how Linux for free works everywhere more or less.
And whenever I needed help here, I've found proxmox personnel actively helping me,
even they didn't have to! Remember this is community support we are talking about and proxmox personnel must cater first for the needs of their paying customers.
If you want to help proxmox and get access to the production repositories you could pay for the so-called
community subscription. I really think that proxmox should rename this to something else, to reflect the main difference to the absolutely free community edition. 115 euros a year buy you access to the enterprise repo. That's all. And it's a dirt cheap amount. If you think it's expensive, ask broadcom for ESXi and you'll get just how expensive things can get.
I'm not affiliated with proxmox. I have found better support by proxmox here for my free community version, than I have found in the VMWare forums
and support as a paying customer. Thankfully the VMWare days are over for me, and we'll start moving our production platforms to the inexpensive paid-for proxmox platforms.