Is it possible to refresh all my tasks at once? It is annoying that every time i want to refresh data i should go Enter coin - Exchange API import - Choose exchange - press Check. It is so simple to create one button "Check all", why i can't find this magic button?

One option when you set up the exchange API import is to have it execute automatically. This will execute the import once a day automatically. This way you don't have to do anything except hit the recalculate button when prompted when new transactions are added. If you don't do that then, yes, you have to click each import function individually. In my experience, magic buttons rarely exist in crypto

It is not about magic in crypto) it is about usability of casual site.) It is obviously, that cointracking is used by people with several exchange accounts, and it is obviously, that they need to refresh data more often that once a day. But instead of hiring more technical specialists, setup cdn and rebuild whole mechanics with API - cointracking team chose the way of limitation its users.
Meanwhile alternative solutions are coming.
https://www.cointracker.io/ for example.