WELL for a start he did what his predecessors failed to do .....he put money into infrastructure he also started US going on renewables as VP he was recognised by all as being very hard working overseas and good at delivering compromises with the Reps he has supported the Ukrainian cause where trump has hindered it the US economy is strong under him ....inflation is making him unpopular but US has less than us and less than most countries ie. good leadership all in all IMO .....not to say I think he should've run for another term at his age
there is such a thing as a statesman but presidents do as you say serve themselves also ....a matter of degree in the mix the one I thought more the statesman and less the polly was Carter - his presidency maybe didn't work as well as hoped but I thought he was extremely well intentioned and a touch unlucky