I love the setting of Brancalonia. I love the humor, I love the folklore, and I am currently learning Italian in evening classes to boot, so this is basically a perfect mix.
But I do not love that the authors picked D&D 5E as the rule system for this setting. Don’t get me wrong, I find D&D 5E perfectly acceptable for heroic fantasy campaigns (and, in fact, I am running such a campaign right now). And I can understand this choice from a business perspective - it makes a lot of sense to tie your setting to the most popular RPG system out there.
However, Brancalonia PCs are not supposed to be great heroes, but fairly unimpressive never-do-wells. The rules deal with this by capping character level at 6, but I feel that this leaves the PCs with too little room to grow and removes much of the proper D&D experience. I’d rather use a rule system that was intended for weaker protagonists, rather than trying to distort D&D into something that is not.
So, what alternate system would you use for Brancalonia?
Pathfinder 2E has a very similar power curve as D&D 5E. In fact, it might even be worse for Brancalonia as characters basically get their level as a flat bonus on everything.
If your bonis flat, talk to your doctor.
If bonis not flat for more than four hours, talk to your doctor.
PF2e has proficiency without level for a grittier experience, but even then I don’t think it’s the best option for low lives and ne’er-do-wells unless you limit it to about level 3. Might be worth looking at Hopefinder, which is a PF2e hack, but the default setting is a zombie apocalypse and I think it relies a lot on short stories.
There’s a rule variant called proficiency without level which removes the flat bonus.