Russia produces Su-57 aircraft according to a plan, which is known to basically everyone thanks to a well-known leak several years ago. No special deviations from it as of yet. So "nothing happened" is a ridiculous position - it'll happen in time, as aircraft is going through production expansion. Probably at one point in late 2023- early-mid 2024 we'll be there.MilitaryWatchMagazine is pure BS and "Russia will have a full regiment of Su-57s ready" is claimed since years and still nothing happened! And even if, I don't think this will in any way change the outcome of this war.
Will they change much? Well, unlikely - that requires different actions from RuAF, and it doesn't seem too interested in changing its playbook. Will they negate changes to the status quo, achievable by new Ukrainian aircraft? Probably.
Will they be noticeable? Well, producing a noticeable margin out of ~100 Su-35s (of which probably less than half operates against Ukraine) doesn't take much time and effort.