That’s an interesting discussion - he seems to find many of the same things I do undesirable in 5E (combat focus most glaringly) but then comes at them entirely differently then I do. Rather then impose goal based XP, which always risks being ‘satisfy the GM based XP’ as far as I’m concerned have you considered how simply using Treasure based XP would work?
5E can be fairly easily modified to different play styles - but I bet if you play with the local 5E crowd your biggest obstacle will be the ethics of play, or playstyle itself - the contemporary trad game ethos seems very devoted to both a sort of power gaming and pre-determined story which can provide climactic moments and smooth progression in short sessions designed around streaming. Combat is favored as its perceived as exciting/dramatic, puzzle solving disfavored because it’s slow (and largely replaced with a thankfully easy to drop skill check system) and role playing frequently reduced to funny voiced plot advancing cut scenes.
The system though is sound and pretty adaptable - I don’t know exactly what you want to to play like but I managed to twist it into a classic Dungeon Crawl system with high risk, grimly gonzo aesthetics and lots of scheming fairly easily because that’s the sort of game the two previous players at the table had played and their Ethos of Play infected the new ones.