Use more windows, not just more tabs.Each Window is a separate instance with it's own threads. Too many tabs and things in them and you start running out of threads per instance (of the program) and eventually threads per program entirely. There is a limit and once you reach it things start running bad no matter how much ram you throw at it.
This is a software problem, not a hardware problem and the best workaround is more windows (at least until you hit that limit as well). Remember, until recently hardware was always the stumbling block, that's changed and software has yet to catch up and take full advantage of it. Even when it does it will be held back to an extent by people trying to keep old hardware working decent because some of the tricks used to make slow hardware tolerable is at times the same that slows newer stuff.
A note about cpu cores since it sort of relates here.
Cores are not as important as people think, that isn't to say they are worthless, just not the end all/be all, I have 6core/12 threads and it's quite common to see most with low loads and just two to four of them doing most of the work (again more instances/windows). Once a tab is loaded/rendered cpu load is reduced so you can probably get by almost as well on 8 cpu cores/threads as you can on 32 cores/threads just so long as you don't open too may tabs at once. Just keep in mind that dynamic content (database, video, animation) on a background tab will retain a load.
I wrote a bit more about it where I did some informal testing
here, but at the time I wasn't aware of what was causing the limit, now I have a better understanding of it. I still can't say it's 100% accurate, but it's informative regardless and may save you from spending a ton of money on parts (hint, for a cheap upgrade look at Ryzen 2000 stuff, there are killer deals going on for it).
DITCH CHROME.I can't stress this enough, it has entirely too much telemetry and garbage that it just eats ram. It also caters to advertising and spends far too much effort handing out info. Switch to Chromium (the foundation of Chrome) or Firefox(!) with a (good!) adblocker or Brave (based on Chrome)which has one built in. This will reduce your footprint by a large amount. Check that link I put in above, you might be surprised at just how much Chrome is eating and wonder what the heck it's actually doing with it all.
Multiple browsersI do it and I've seen many others do it as well. Separate things out between multiple browsers, this way you can get more before things start lagging. Better still, if one crashes you only lose some of what you were doing. This may not be as big a deal as it used to be but it still helps separate data and allow you to have more going at once.
Ditch Windows.I know it's not always practical but Linux and Mac will use far less memory on top of what I said above. Not sure about Mac, but Linux will also spread the load over the cores better.
When I was doing that testing, while it was on purpose to hit the limit quickly, I wasn't really able to ever use a ton of memory like I could on Windows, and yet I still had many of tabs open. You might read it and think it was only 30 tabs, but they were 30 tabs picked specifically for their ability to flood out the system due to lots of dynamic content. Had they been static pages it would have been in the hundreds.