Check your emails: a white screen should make WordPress send you an email saying there’s a critical problem and inviting you to fix it.
Could caching be stopping wp_debug from working yet? (Clear cache)
If renaming plugins folder doesn’t work, try moving the current theme directory out of the /themes folder. Ensure the /twentytwenty theme is in the /themes folder so that it defaults to that.
Do you have a backup of the database?