No hurry

Good summary from Lowell, but I'll add a couple simple thoughts.

Column encryption is is designed when you trust the server, not the client. You need to trust admins...

apt-get update
apt-get install mssql-server

I like Linux updates.

we could use another one, so please feel free.

This appears to be an issue with IO not being able to be frozen: https://docs.microsoft.com/en-us/sql/relational-databases/system-dynamic-management-views/sys-dm-os-wait-stats-transact-sql

Did previous log restores complete? Are you restoring in standby or norecovery?

My suspicion is that there is one of two things happening.

1. The powershell exe isn't firing for the account in services (not in path, or something else)
2....

That looks like an incomplete command. Do you have Powershell as the program being run? Are you use this is in the path for the system?

I'd do something...

I tend to trust Microsoft as a company. They have made missteps, but none that I consider egregious. I think far, far too many people seem to distrust them for...