I’m thinking go rogue with the folk hero background.

Rogue: You know your line of work brings enemies. You’ve learned how to get out of tight scrapes quickly and discretely (Cunning Action, stealth) and how to sucker punch and run (sneak attack.) You always carry a dagger for protection, and picked up a rapier and shortbow when the heat was picking up just in case you got jumped.

Folk hero: You started as a commoner, and gained a good reputation for being able to take the celebrities down a peg. The people love you, but the establishment wants your head. Choose the options involving a tyrant for the defining event and flaw: you insulted their favorite bard, and now you’re in trouble.

Choose Calligrapher's Supplies as your artisan’s tools, since you write your critiques in style.

Stats: Dexterity and Constitution, in that order. The rest you can put wherever. Put Intelligence third if you want Arcane Trickster, otherwise Wisdom is always a solid third choice.

Subclass you can figure out at level 3. Inquisitive and Arcane Trickster may be viable options.

You might want to look into an College of Lore Bard.

Vicious Mockery works great for an overly critical critic as do Cutting Words.

You could flavour both as insightful stings against the opponents abilities like how his swordsmanship lacks finesse etc.

Charisma is the most important stat for a successful Bard, but it kinda sounds like this person is unlikeable and not even a good Bard, so they would probably have bad Charisma. You can always make your character bad at what they are meant to do, but it will probably get old pretty fast when you’re useless in most situations.

I would recommend just not choosing that class. Maybe pick a background that gives you proficiency with a musical instrument, but even then, it’s probably funnier if they can’t even play. Then choose a completely unrelated class that doesn’t care about Charisma. Maybe they’re a Wizard who read about Bard spells and tries their best approximation while singing and playing poorly. Or maybe they’re just a Fighter or a Barbarian who has to learn to fight off haters while continuing to talk shit.

If you do choose to play a Bard, I would just give yourself high Charisma and role play as an insufferable asshole anyway. At least that way you can have some magic that actually works. Or you could forget Charisma and spell casting and lean into something like College of Swords Bard and focus on Dexterity and Constitution. You’d be better off just picking Fighter, but at least this way you could actually cast spells poorly for the joke. You’d just be hamstringing yourself in the long run. Maybe they are a Bard at level 1 just for the basic spells and then start taking levels in something else when the Bard stuff clearly isn’t working

He has no experiance in ever fighting anyone or anything.

Don't forget your character should have a reason to be with the group and fit with them and go adventuring. Not knowing how to fight is commoner-levels of skills and will force rapid character progression from the start.

I know this has been pointed out, but...

He has no experiance in ever fighting anyone or anything

Nooooope! He can fight. You're an adventurer. Maybe you come from humble roots, but you are now a roaming mercenary who fights for money (and maybe a few other things). Make sure you can work with the rest of the party. Make sure you bring value to the group both in and out of a fight.

As for the character concept...

in a world with bards, there had to be critics too, right? So this character had a weekly column in some newsletters published from town to town (is that a thing?) and developed a reputation for being a snob. He barely ever hands out a score higher than 6 out of 10.

His only real talent seems to be intuitive analysis and articulate critique - skills that have helped him at what he does...

College of Eloquence Bard. Just don't play him elequent. Instead, use his great powers for "evil" (not literal evil). To tear down the art of others and crush the confidence of his enemies into dust.

When Giants attack, he makes them feel small.

When Gods rage, he gives a solid, "meh...6/10. I've seen better."

When Barbarians rampage, he makes them cry...

"It stinks!"