What are the best alternatives to LXD for a growing business?

Proxmox usually comes highly recommended, though the best choice really depends on your budget and needs. Before going all out on expensive licenses, consider what you really need and how secure your current setup is. Are you using secure protocols and employing proper authorizations? You may want to evaluate your security and scalability going forward. If you have what you need, extending Proxmox might work well. For something more advanced, consider hiring someone to manage your infrastructure or looking into managed hosting options.

Coolify is a solid pick if you want a PaaS vibe without hefty monthly costs. Check out Proxmox if you're looking for actual VMs instead of containers, but be prepared for a bit of a learning curve. Kubernetes is powerful but might be overkill for a small business and very complicated to set up. Docker Swarm offers clustering that makes sense but its popularity is waning. Coolify should provide a better experience than just using LXD from the command line, so you’re on the right track.

I'd be cautious with Coolify. It might complicate things more than necessary, especially with adding layers that don't provide much benefit. Backups and restores in Coolify aren't great since they only take care of internal database and config. Proxmox is generally more reliable, especially with backups, and gives you the flexibility of using LXC or VMs based on your needs.