I've experienced the problem where Windows 10 machines seem to be stuck on checking for updates, etc. when using the Settings | Updates & Security and selecting Check for updates.
To resolve I open cmd and type in
usoclient startinteractivescan and that seems to make it rescan and start downloading and/or installing, and move forward from being stuck.
I've read various posts about
usoclient and it being part of the Update Orchestrator Service process and having various system Task Scheduler tasks scheduled. I've not been able to find a lot about
usoclient and it's command line options from Microsoft though unfortunately.
I'm guessing the issue is related to checking for updates during the Active Hours period and the GUI option "Check for updates" not allowing it to move forward with whatever it's stuck doing.
In some environments there could also be group policy settings that configure Windows 10 update configurations which contribute to the process potentially.
Additionally, a few years back I wrote about things you can try to resolve this for other Windows Operating systems on Downloading Windows Updates takes forever which is rather comprehensive and some of it may still apply to Windows 10.