Vlad To be more precise... (I'm no UX person but I'll have a go)
Simple Approach
A new pane at the top or bottom of Personalized Results which has a toggle switch, the same style as the toggle switches in the Search settings.
Include Paywalled Results
Whether or not sites known to have paywalls will be included in results.
This includes sites that may require payment or creating an account to view the page.
ON (by default)
(Originally I suggested a new toggle under Search, but after having another look, that page is really about widgets, not search results.)
Additional Flexibility
Underneath the toggle switch add a table with a title, similar to the one already on Personalized Results.
Explanatory title:
If you have an account on a paywalled website, add it to this list. Results from these domains will be included as normal even if Include Paywalled Results is switched off.
Table format:
Domain | Date and Time |
nytimes.com | Dec 09 2023, 17:23:20 | X (delete)