Boot Camp assistant stuck at disc partitioning

I've recently decided to install Windows 10 alongside masOS Mojave on my 2019 iMac. Here's the system:

Basically I just downloaded the latest ISO from Microsoft website and followed the instructions in the boot camp assistant, after several minutes of waiting it just stuck for more than an hour:

So I closed the assistant and then barely managed to restore default disc partitioning via disc utility (boot camp kept telling me it couldn't restore things as they were) , and then tried to install Windows once more - same result again. What should I do?