I was in a similar situation last year. So I put everything in a subdirectory, pushing bookmarks, etc, into an email-like structure. Then I wrote a script to count how many things there were to deal with, and chose an arbitrary deadline of Nov 30, 2019.
I had nearly 5000 items.
That told me how many things I had to deal with per day, and more importantly, for each day, it told me my target for how many there should be remaining, and how many did actually remain.
I then wrote a script that listed the oldest 5, the most recent 5, and 5 chosen at random. Every day I ran that script and without fail dealt with those items. The mantra was:
* Delete;
* Defer;
* Delegate;
* Deal with.
"Defer" doesn't simply mean "put off" - it means that it is waiting for something before it can be done, so it goes in a special "pending" queue.
Then I also processed items that let me hit my numbers. Some were easy and I could far enough ahead of the game to let me take a day off, but mostly I just ran my "Choose 3x5" script again.
There were days when I slipped, and days when I got further ahead, but by November 1st I was down to under 200 items to deal with. And I've stayed at that, but now it's churn.
The secret, I found, was to have destinations for everything. Look at one of your bookmarks - why are you saving it? Where should it go? What should you do with it? Does it fit in an existing project? Do you need to create a new project? Should you simply file it for recall later when you need it?
* Does it require action?
* Should it simply be filed?
In my case, things built up because I didn't really know what to do with the thing I was looking at, so it went in the "Queued" pile and festered.
Deal with 10 things. Have destinations for them all.
Then you've made a start.
With regards to bookmarks.
* Websites you regularly read can stay as pinned tabs. If that costs too much RAM, bookmark them.
* Websites you read irregularly, can be put in bookmarks.
* Websites you'd only read once can be put in some kind of logging application such as an RSS reader, OneTab, etc.
I also believe something like Monica [1] can help with some issues. For example, say you're saving up items to buy as a present for your beloved one. With Monica, you could just link these in the CRM to the specific person, organized, and you also get to see what they got from you in other events. In that sense, I suppose "Deal with" is rather broad.