I agree to be honest. He was defeated and outclassed by the best pound for pound heavyweight boxer in the world. There was no shame losing to Usyk, even Fury has clearly ducked a fight with the Ukrainian. Franklin was no pushover and like you rightly pointed out, many people thought Franklin was a deserved winner in his fight against Dillian Whyte. While Joshua easily beat Franklin on points last week.
Losing twice to Usyk has not done him the best of favours psychologically, but in terms of ability, Joshua is still there amongst the best. In my opinion, only Usyk and Fury are better than him in the heavyweight division right now. I would potentially also say Joyce, but Joyce hasn't fought as many big names as Joshua has, so it's not clear if he would win if he faced Joshua.
Joshua should look to fight British heavyweights Joyce, Dubois or even another fight with Whyte. Wilder would also be an interesting fight for Joshua, as Wilder has more power than Joshua in my opinion, but I think that Joshua is probably the better overall boxer. Beating an American like Wilder would catapult his status once again as a top heavyweight. I think a fight between Joshua and Wilder would be 50/50, but it would be a very dangerous fight all the same for Joshua. From what I understand, Hearn has Whyte lined up as Joshua's next opponent. I am sure that Joshua would win once again against Whyte, if this rematch is eventually confirmed.