Help me build the combatant part of a Jaskier/Geralt-duo

Me and some friends are gonna start a campaign soon and we are only two players. The other player wants to play a more roleplay-oriented bard, which is completely fine by me, but it means my character will have to do the majority of the fighting, it’s basically the same dynamic as Geralt and Jaskier from The Witcher.

We are starting at level 3 using the standard array. I am thinking of picking up sentinel so I can keep enemies away from the bard, but else than that I don’t have a definitive idea of building a strong martial character. The bard will pick up some buffing spells too but isn’t built for effectiveness in a fight.

Please tell me any ideas or builds you have for such a character, UA and even balanced homebrew content are acceptable.