Even if Ma Chao was a warlord, I don't think there's a need to exaggerate his combat abilities.

‌While he did lose a one-on-one duel against Yan Xing, there is room for the excuse that he was still a young boy around 18 or 19 years old.
If you read the Records of Ma Chao, there are a few passages where it is inferred that his physical strength was quite exceptional (such as the anecdote about him intimidating Xu Chu, or his adoptive father's evaluation), so it is possible to assume his individual martial prowess was relatively strong.
However, I don't think we can say he is much better than Zhao Yun or even incomparable just because of his experience leading a regional warlord faction.
Ma Chao essentially inherited the foundation his father built, but in the end, he blew it all.
His only recorded instances of victory in war were the battle against Guo Yuan and the fall of Jicheng. But Guo Yuan wasn't particularly a famous general, and Ma Chao didn't even lead the army as a commander in that war; he merely participated as a low-ranking officer, and it was actually Pang De who achieved the merit.
Regarding Jicheng, he did lead the war as a commander to some extent, but his military force was only around 10,000 men, and all he did was besiege a city of 1,000 enemy soldiers for a long time until it fell... and even then, the opponent wasn't a particularly renowned general.
Aside from that, he was defeated by Cao Cao, failed against the Longxi rebel forces, fought Xiahou Yuan in Mount Qi, tried to recover Liang Province using troops from Zhang Lu, and fought against Zhang He in that process—he failed and was defeated in all of these.
Ultimately, he lost his own base, wandered around, and eventually sought refuge with Liu Bei.
Can we really say that a person like this is on a different level from someone like Zhao Yun or is a much better fighter just because he has the experience of being a warlord leader? There is no particular evidence to suggest that his field command abilities are better, let alone his individual martial strength.
I wouldn't go so far as to assert that Zhao Yun is stronger, but I think it is unreasonable to claim that Zhao Yun is not even worthy of being in the same conversation just based on the single merit of having been a warlord leader.