Site-wide issue: 'Disable on Phone' checked on all modules — mobile shows white/partial screens

Hi Divi support team,

I'm running Divi 4 and have a site-wide issue I can't explain.

The 'Disable on Phone' checkbox (Section/Row/Module Settings → Advanced → Visibility → Disable on: Phone) appears to be checked on every module, row, and section across every page of my site. As a result, mobile visitors see a white screen or a mostly-blank page on most pages, while desktop displays correctly.

Website: roelcrabbe.com
Divi version: Divi 4

I did not manually set this. It seems to have been applied site-wide. My questions:

1. What could cause 'Disable on Phone' to become checked across every module/row/section on every page at once? (e.g. a Default Preset change, a Theme Builder template, a corrupted database value, an import?)
2. Is there a way to bulk-uncheck this site-wide without having to open every module on every page individually?
3. If this was triggered by a Default Preset modification, can you walk me through reverting it via Global History States, or another reliable method?

I'd really appreciate your help — the site is essentially unusable on mobile right now.

Thanks,
Ehasanul Haque