I have to agree with @fredrike recommendation, I’ve been running hass as a VM in DSM 6 for a very long time and it runs flawlessly.
In the dark ages I was running it on docker and it was a nightmare most of time.
Go for VM, it’s a clean install that gets everything working from base, restore your last full snapshot, and enjoy.
Now concerning DSM 7, I’d like to be sure someone had upgraded with no issues from DSM 6 to DSM 7 using a AEOTEC Z-Stick Gen5 and on hass running on VM, before I commit to the upgrade.
I have so many things working on Z-Wave that upgrading to DSM 7 as appealing as it might sound is out of question if that means loosing Z-Wave.
If anyone reads this and can confirm HASS on VM with AEOTEC Z-Stick Gen5 runs fine on DSM 7 then please post a heads-up here so that others like me can take a deep breath and go for the update.