Yeah, YouTube is using much better tools now to detect SMM activity.
Most SMM services leave fingerprints on the accounts they use, so if one proxy or account used for comments gets blacklisted, YouTube can connect this activity with your channel too.
That’s why many SMM panel accounts get banned.
This is why a lot of people move to phone farms and build their own setup.
You control the behavior of the accounts, so you don’t leave them running 24/7 watching random videos from every country and language.
With a phone farm, the activity looks much more natural, closer to real human behavior, so it’s harder to flag.
And if you know real programming, you can build your own system, or find some serious software provider that keeps updating things every time YouTube changes something.