2. Delete. Flag what you need to save and delete everything else (or vice versa, filter and delete anything you don’t need). A fully clean inbox/browser will provide daily motivation to keep it clean.
3. Review all your bookmarks/tabs, etc and identify 10-20 general themes. What are you interested in? Can you start an activity or program that would allow you to review some of your favorited content in a more organic fashion?
To-do lists can be off-putting, and I doubt you would ever sit down to read through hundreds of webpages in abstraction. By applying it to a project or educational program, you will have a tangible product/outcome, and find that you don’t need as many bookmarks on that topic. (Or maybe you’ll create more.. at least, they’ll be different).
Whenever I do this, I find myself deleting about 10% of bookmarks with every new project (and adding back less than that).