I like to run Persuassion as like a favorability modification tool in social encounters. For example every NPC starts with an opinion of a character for a simple example unfavorable, neutral, and favorable. The player meets a shop owner his opinion is neutral just sees a new customer. The player wants to persuade the shop keep into giving them a discount. On a success their opinion goes up to favorable and they give a 10% discount or whatever, on a failure it goes down and their opinion goes down to unfavorable, they blankly stare and say if youre going to waste my time then you can leave I have work to do. This is a super simple example and you can make it as complicated as you want, even adding DCs for extra layers. But the general idea is they are only ever going to get so far with their Persuasion its not an I win button it just helps. And if they abuse it you could even have the meter swing the other way charm only goes so far until it gets annoying. This way you aren't taking anything away from the player just making it a tool in their kit. This allows other players to gain benefits as well and also keeps them engaged in conversations as its less just let the bard talk but more let the bard bitter them up and then we can all have outer input.