Unfortunately you are exactly right about what DRM/TPM is going to do to computers. Once Windows 11 reaches 50% marketshare, some Western government is going to demand that ISPs in their country not allow anyone online unless they are using a government-approved OS. Then they will require OSes and app stores to ban Tor and E2E encrypted chat apps.
Perhaps they won't go so far as to kick Windows 10 computers off the internet, but they might at least restrict them to certain sites and protocols. They could also say that people running "unsafe" OSes must install a government-issued CA certificate, to allow TLS interception.
Web hosts don't generally need to make outbound connections, but in any case, companies will be allowed to register specific domains / IP addresses with a government regulator, on the condition that they don't support E2E encryption (and, depending on the contents of the site/service, they may have to hand over a copy of their TLS private key, and not use forward secrecy).
Also, of course there will be government-allowed Linux versions, which implement Secure Boot and have a package manager that only installs approved apps. Admittedly, I'm not sure if this theoretical government would stop people writing their own software, but they could demand that OSes only allow "approved" apps to send packets over the internet. This would also prevent people developing "piracy" apps.
It'd be too cumbersome, there'll always be a new 'hack' to install a different package, then there's the ability to inject your messages and to send over these 'approved' apps and little to no way of ensuring such a huge infrastructure are all up to date on 'security' patches which stop these exploits.
Perhaps they won't go so far as to kick Windows 10 computers off the internet, but they might at least restrict them to certain sites and protocols. They could also say that people running "unsafe" OSes must install a government-issued CA certificate, to allow TLS interception.