Likely it is running a big update package in the background. Just give it a while, like a few hours. If you haven't booted it up in several days, that could be the reason the update is so big and takes so long.
With Win7, it tells you when the updates are downloading and when they are installing. Win10 just does it all in the background.
I don't recommend you turn off the updates. Quite often they are security patches, and a system that has not been updated in a long time is vulnerable to viruses/malware.
You can google how to "turn off updates in Windows 10" and find good instructions. What you can do is turn them off when you are on limited data or time, and then turn the updates back on at a convenient time. The updates then should start downloading and installing when you connect to the internet. Just DON'T leave it off indefinitely.
A lot of people don't like Win10 but it is by far the most smoothly operating system ever from Microsoft. However, the developers didn't take into consideration that not everyone has unlimited fast data.
If the sluggish behavior continues, reboot and see if that helps.
Single empty-nester in Middle TN, sometimes with a friend or grandchild on board
