Wow! You've got a lot of detail. Very nice
I'm grappling with the same issues, trying to make a continent and the scale right... and I am not an expert in any way.
I've been looking a bit at tectonic plate movements, climate zones, and how rivers and lakes are formed. There is a lot of that kind of info on YouTube.
It's tough to get it right and I have to remind myself that it does not have to be perfect.
Ink_alpinist's comment about elevation is a good place to start, and if you look at topographical maps of Europe you might get some ideas, for both mountains rivers and lakes.