Is the screen the Mustang car with a progress bar at the bottom?.
If so, that’s the reformat phase, so yes, it will be just fine.
Just make sure to configure syn3updater accordingly, that is, 3.3.xxx as current build.
It will create a reformat USB.
The link on my DB is not HTTPS if you are trying to connect via HTTPS it WILL fail, this is likely your browser or something called “HSTS” you will need to force HTTP or clear your HSTS settings in your browser.
Sure. To avoid downloading everything again, once you install syn3updater and select a download location for the files, copy the already downloaded files into that folder before starting the process.
That way, Syn3updater won’t download them again, it will just verify they are ok.