I had a huge hosts file which I found (cannot find the site now, I seem to have lost the URL), it was so massive, I needed to change some service on Windows to prevent issues on start up. Sometime last year, Windows defender completely blanked out the Hosts file to default empty state.
I re-downloaded the file and added an exclusion for it and I just checked it now, and its blank again. After the first time I invested in a pi-hole.