I had exactly the same issue. The solution is Windows LTSC (long term service package). It has no Cortana, teams, or Windows store, no Telemetry, and only update about once a month and it never updates automatically, only when you allow it to. It’s designed for applications where a computer has to be stable for a long time.

A copy can be a pain to get a hold of because Microsoft only want to licence it to corporate clients, so it’s usually not possible for individuals to buy a licence at any price. Microsoft really don’t want regular people to have access to it.

but if you look on your favourite piracy site you should see it. Then use a Windows keygen and presto it’s activated.