If you have something open because you need to finish a task... Put the task explicitly on your todo list, set a reminder, and close the tab.
If you have something open that you are need to finish reading reading but don't immediately have the time? Add it to your Pocket or alternative, and close the tab. If you feel you might forget it, set a calendar reminder to follow-up.
If you have something open that you think might just be nice to reference for that project you're kinda tinkering on... Summarize your finding in a way that would be meaningful to a future-you searching for that reference. You can do this in whatever method you prefer (bookmark, txt file, journal, pocket, etc.) And finally, close the tab!
In my personal experience having tabs open for weeks, to years on end did nothing more than exacerbate my anxiety over the fear of somehow missing out or loosing that information.
Give your working brain a rest and externalize this effort onto something that you aren't constantly being reminded of every second you're using the browser.
If you're worried about not finishing something, give yourself deadlines and set reminders.
If you're worried about not finding something, make it easier for a future-you to find it.