Happy new year!

I have followed your suggestion: a fresh VyOS install in a VM and tried to load the current configuration. Here are the errors I get:

That means I should create a new VyOS instance and then load my current configuration in order to spot any migration error. I can try that.

I have tried to move to the rolling version vyos-1.5-rolling-202312231415-amd64.

Sure, I will do that and report here the outcome.

I have tried to migrate to one of the last nightlies and now the situation is much better: vyos reboots, does not hang and I can ssh.
There is still an error in the migration script:

I would like to contribute with a PR about this. At the same, time I would need some guidance on identifying the conditions requiring the onlink option to be added.

That is my first PR; please, let me know if you need something else.

OK, I will.

@Viacheslav My addition of the onlink option is really brute-force, applied blindly to everything just to see if that was a solution and give you more information. I do not think my "fix" is really ready for a PR.