Weird update behavior/stuck

I have a W10 laptop (Inspiron 15z), that hasn't been used for about a year (now at build 10.14393.0). When I try to update it with Windows update, the following happens: 1) it says updates are available, but get stuck on downloading updates 0%; 2) after hours, it shows several updates are available; 3) when I select download updates, they disappear one by one almost immediately; 4) then it goes back to step 1 and history shows no downloads were installed. In fact, none of my previous updates show either.

I tried the Update troubleshooter and it says it fixed some errors but could not fix "potential windows update database error detected".