I think at least against 4s he could try to move his quick feet and try to stay in front of defenders.Well, by the same count he will be equally overwhelmed defensively at the 4 against the likes of Giannis, Zion and Banchero. In reality, he will not be facing them but play against bench 4s and 5s. He could be OK against bench bigs.
Also he could use his length to cover up some of his deficiencies somewhat.
Maybe in the future he could guard physical 5s but he’ll need to bulk up significantly for that imo.