[mangoandmimi]

I reckon a lot of it is to do with the very empty cage he has. Also noticed he has no house for sleeping in, a log lets too much light in and no sound barrier so I doubt he feels very secure. A cardboard box with no bottom will do for now but take a look at some of the guinea pig houses which are a good size.
eta: Also, giving shredded tissue will allow him to make a proper nest which I think will make him much happier. As far as I’m concerned, if you can see your hamster sleeping like with that log, then there isn’t enough privacy.
As for the empty cage - definitely fill it right up! The cork tunnels & hyacinth tunnels from zooplus are big enough. I’d also add some levels in as they serve as a fall breaker and sheltered area. Mugs, jars, egg boxes, cereal boxes, rat sputnik, more bendy bridges, branches, grass/hay balls - anything really. Look for rat sized toys as they’re a better size.

Sounds like you’re taking all the right taming steps but 3 weeks is still early days, the cage filling should definitely help. Not all hamsters tame quickly and some really do take months so don’t be discouraged.