However I find it very unlikely that the performance was increase considerable enough for the better variants to not be roughly comparable to the worse ones.
I’m not taking about structural limits, that gets a multiplier of 1.5.
I’m talking about sustained turn rate, which is basically how much can a plane turn when sustaining a set speed.
The Americans anti-Soviet propaganda about the MiG-23 even in red flag exercises definitely aided the belief that they had poor turn rates etc. It was as good or better than the Phantom and had superior flight performance otherwise with some exceptions.
The radar and weapons systems were inferior, and the range was not as good. There are pros and cons, but the MiG-23 was a fantastic aircraft once the teething issues were resolved.
The vast majority of 4th gen fighters considerably overperform by unbelievable margins, this is not really a massive concern imo. Gaijin is unwilling to fix the F-5 series either, which overperform by such a large margin… the F-5E outperforms the real world F-20…
Gaijin’s statement on those is “they’re old, we will leave them as-is and are not interested in fixing them”. (They didn’t want to nerf premiums that sell well).