Feats in 5e are quite strong, and if you are in a group that uses them (let’s be honest, who isn’t in such a group?), chances are you have more than 1 variant human in the bunch. While there is nothing inherently wrong with the variant human, if you are playing in a fantasy game with a plethora of different and unique races, you don’t want people thinking that if they want to be the best <insert class here>, they need to be a variant human.
The easiest way to address this problem is to grant all characters a feat at level 1 and to ban the variant human. While this will have the added consequence of making all characters slightly more powerful, it will standardize the so-called attractive element of the variant human between all races. The power boost this provides will also taper off as the party gains levels. At lower levels, the power boost should be noticeable, while at higher levels, it won’t be. You can get around this by making encountered slightly more challenging. Maybe add a few minions of CR 1/8 or 1/4 to the encounter. Maybe just make the encounter +1 CR of the party. Maybe just add some extra HP or damage to the monster.
You could also prevent players from having too high of ability scores at level 1 by restricting the feats they can choose to racial feats and feats that do not provide an ability score increase. Racial feats are a nice role playing enhancer and will not necessarily provide a massive power boost to the party.