URGENT: Fix WordPress White Screen Issue -- 2

I'm experiencing a persistent issue with my WordPress website where it loads and then immediately displays a white screen. A freelancer fixed in a bit the issue, by showing the content right after the blank screen - but this is not the ideal way to go. This problem appeared out of the blue, and I haven't made any recent changes to the website's code or files. I've already tried disabling all plugins and switching to a new theme, but the issue remains. There are no specific error messages or logs visible in the WP Admin area.

Key Requirements:
- Diagnose and resolve the white screen issue on my WordPress site
- Identify any underlying problems that might not be immediately visible
- Ensure the website loads correctly without displaying a white screen

Ideal Skills and Experience:
- Strong expertise in WordPress troubleshooting and debugging
- Experience with resolving white screen issues and similar WordPress errors
- Familiarity with server-side diagnostics and error log analysis
- Ability to work efficiently without direct error messages or logs

I'm looking for someone who can quickly identify and fix this issue to restore normal functionality to my website.