I’m usually a size 37 (don’t know what that is in US), but when I wear flats and walk my heels keep coming out. But when I wear size 36, it’s too tight! I always buy brand shoes because I feel that shoes are important but even those quality shoes seem to have problems..How do you guys deal with this?
To —what little socks lol? can you give me a link?

There are "little" socks, made just for flats. They have them at Steve Madden. Idk if they have that wherever you are. You can’t see the socks once you put the shoes on, but they are comfy. & If your flats are leather, your feet won’t stick.