This may not be relevant, but I had a similar problem when I upgraded from 7 to 10 via the automatic download about 18 months ago. Afterwards my PC was very slow starting up and closing down, it could easily take 2-3 minutes, long enough to make a cup of coffee! I tried most of the solutions suggested in various posts above and others, all to no avail. Then my SSD started throwing faults, Windows was repairing it quite often. So I decided to bite the bullet, get a new SSD and reinstall from scratch. A lot of hassle I will agree, but afterwards it now takes less than 20 seconds to boot after the BIOS has transferred control.
Obviously you need to have the installation media for any software you want on the machine, but at least you can dump the bloatware and in my case, several years of old, no longer used stuff.
If you do go this route, remember to register your current (in my case the free upgrade) by opening a Microsoft account. This way you can reinstall from a downloaded copy for free. Just re-log on to the account and MS should activate the install.
ALSO TAKE BACKUPS, THEN TAKE SOME MORE!! A disk image would be good as well so you can at least get back to where you started if anything goes very wrong.