It's interesting to realize that really, that's all that Ford though Han Solo was.
But with Indiana Jones... Ford cares about that character.
Yes. Truth is, I think 'Solo' and Alden Ehrenreich weren't bad at all. That actor & movie just showed us exactly what the Han Solo character was on its own.
The epic story of the OT + the star power of young Harrison, it all elevated the character way beyond what he was back in the day. But Harrison had to play the character several times, being worried about failure before ANH became a hit, and he had no illusions about it.
Although, to be fair, I don't think Indiana Jones had much depth until the 3rd movie. In 'Raiders' he was basically James Bond with an ex-GF. In 'Temple' he was Bond with a sidekick.
Indy seemed deeper than James Bond from the start. But it was mainly because he got beaten up more often and he didn't act like a literal sociopath the entire time. It was plausibility more than depth.