Romero arguably beat Izzy so I don't agree, it was heavily publicized that Romero had a shitty performance, but he got the most out of his 42 year old body. Despite the fact that Vettori landed 4 takedowns during the fight, he was the vastly inferior offensive and defensive fighter compared to Romero.
Adesanya outlanded Romero by a mere 8 strikes, with more than 50% of his total strikes landed being leg kicks. Yoel oulanded him in the 1st and 5th rounds, while landing at a 44% clip to Adesanya's 36%. Yoel landed more head strikes and clearly landed the more significant punches throughout the fight.
If Romero was a few years younger and had more juice in the tank, I think he beats Adesanya. Romero was the only guy wise enough to know his limitations and Adesanya's strengths, he didn't waste too much energy chasing Izzy around the cage, and he exposed many deficiencies in the striking of Adesanya.
In terms of legitimate championship performances(not interim belts), a past prime Romero gave Izzy his most stiff challenge. The 2015-2016 Yoel that destroyed Lyoto and Weidman would have a massive edge over Izzy, even the 2020 version went tit for tat with him.
Fans were so let down by Romero not engaging in a super high paced fight, that they ignored how close the fight actually was and didn't think Romero deserved to win because of this perceived lack of effort, which could also be considered great strategy. As Romero gave Izzy statistically his toughest fight, and was the first guy to really shut his offense down and reduce him into a 36% striker who struggled to land anything but leg kicks.
