No it doesn't, it just makes the Wrath more impressive than you give him credit for. Consider that Fulminis, who Sel-Makor states Baras is greater than even before the amp, was the premier sorcerer in the Empire who even the Dark Council goes to to learn from, is said to have once obliterated an entire city with a lightning storm and was planning on channeling a planet-wide attack.
Is said by whom? Because Khem also claims Tulak could solo "an army a thousand Jedi strong", which is pretty ridiculous and clearly a hyperbole. If the source isn't reliable, we can't trust it as fact.
Even if true, when we consider Fulminis was particularly gifted with sorcery, it makes a lot of sense to assume that this lightning storm which engulfed a city was a ritual of some kind, rather than an actual combat-applied ability. So, sure, Sel-Makor states Baras is greater than him. Baras being a greater fighter than Fulminis isn't that impressive, considering his specialty were rituals and sorcery and is featless in other aspects.
The codex.
Sel Makor doesn't say Baras was better in combat. He just says he was greater than him all around. Sorcery still draws on someones raw Force strength and the top sorcerer in the Empire, so highly regarded that Vitiate personally entrusted him to help carry out his century-long long plan, would be among the very strongest Sith in the Empire. Baras was greater even without Sel Makor's strength. Theres a reason Baras is called "nigh-invincible" and could cow the Dark Council into accepting his coup.
We've seen people who are great sorcerers and illusionists but not great duelists or fighters, so being a fantastic sorcerer does not mean you are an all-powerful Force-user overall or necessarily well-rounded.
Sel-Makor stating Baras is greater than Fulminis doesn't mean that much, anyway. Traya, at the end of KotoR II also states that Surik is the greatest of her students, and that certainly does not put her above Revan.
In any case, if we power scale, it's noticeable that Baras is a lot of hype and not so much more. Baras < Wrath < Dooku < Revan < Valkorion < Sidious < Luke [you could maybe swap Dooku and Revan/Valkorion and Sidious, depending on how you rank them].
There are a lot of other powerful individuals that could go between the Wrath and Valkorion which would make them superior to the likes of Baras. He has some accolades, but he needs feats to back it up, and he nearly has none and gets his ass handed to him by someone who is inferior to Dooku or Revan.