The Skillwise GOAT, that's a new one
You can rate a fighter based on his achivements, or based on his skills.
Which are too different things. Casual. You cannot compare fighters from different eras, because the sport is evolving and did not peak yet, 2025 is more competitive than 2020, 2020 is a lot more competitive than 2015.
Khamzat is the goat skillwise, not achievement wise. He do not even have one single title defence, but he is skillwise the best MW ever. That's a fact. He could beat all MW of all times, at least would be the huge favorite. Anderson Silva, even with his title defense, would get mauled by Khamzat as he was mauled by Chal Sonen, bringing only a puncher chance.
Also, Khamzat's career is not finished, Anderson Silva career is. Khamzat era is a lot more competitive than Anderson Silva era. Facts, facts.
You cannot rate fighters based on achivements, since they are from different eras, and some era are simply more competitive tougher than others, but you can do that with skills.
As Khamzat would destroy all MW of the past easily, probably, so does Topuria, he would destroy all FW of the past, easily.
Casual.