One issue with rollbacks Arch has is that there's basically only up to three valid configurations available at any time. These are your current system configuration (oldest state), upstream repositories (newest) and your local database copy (somewhere in-between, though all three states can be identical, e.g. straight after Syuing). By definition, you can't convert your system configuration back to an older one because it's the oldest one of the three already. What you can do is mix your current oldest configuration with packages from the cache, older or newer doesn't actually matter. But you're not getting back the old state really, you're creating a new one that's different from Arch's repository.
A configuration on NixOS includes all exact package versions and their exact configurations. No exceptions.
If you actually need these guarantees is a different question. I used Arch for 15 years and never had significant issues. I switched to NixOS instantly after trying it on an old notebook and immediately recognized that the whole approach suits me so much better that I switched almost all machines over by now.
Mint widely regarded as the best distro for advanced users? I must have missed it.
Not trying to shit on it or anything, but I've never heard the sentiment.