That's functionally it. Instead of quick connect I just run Tailscale/OpenVPN if I need to access it away from home. You also can't get easy SSL Certs in the gui, but it you can get them yourself and upload them if needed. If you DIY, your CPU also won't show up correctly in the GUI, but works just fine. Otherwise, I don't notice anything missing.

There's a few different loader options since DSM 7.x, but I've been using "TinyCore RedPill Loader Build Support Tool ( M-Shell )" with zero issues throughout multiple updates. They've even semi-recently gotten it working to support auto updates with no manual builder reloading. Much lessy finicky that the DSM 5/6 days.

So yeah, it's grey area bootloader... but I've been using it daily since 2016 with no real issues.

I bought a used Datto NAS and put xpenology on it. Without drives, $300 got me 4 bays, 1 internal 2.5", dual 10gb nics, and 32gb of ecc ddr4. If you're ok using the hacked bootloader for synology's os, it's hard to beat.