Multiclass help

I just beat chapter 1 of the OG campaign with a character with 4 levels of paladin and 1 level of fighter. Really enjoying the build so far, the extra level of fighter giving an extra attack is huge, and greater cleave basically makes my attacks AoE. I'm tearing through normal enemies, and while bosses can be tough, I haven't hit any major walls yet. Using a longsword and shield.

Wondering where I should take my build from here. I'm not interested in min maxing, but I also don't want to kneecap my character for later content. I wouldn't hate more spells/abilities - would a level of bard be useful since I have high charisma, or do the good abilities only unlock at later levels? What other multiclass possibilities are out there?

I find it difficult to parse just from level up menus where I'll get multiclass value from just investing a handful of levels. I found the tip for one level of fighter for the extra attack online, any similar tips of quick wins through multiclassing would be appreciated.

Thanks!