The winget package manager should already be installed on updated systems, but if not, you can install it from the Microsoft Store app. It is listed as 'App Installer' and is authored by Microsoft.
Oh whoops, I should close some windows, because I currently have 623 open tabs in Firefox across 107 windows. It's working fine, even with all my plugins running. Firefox is good at unloading dormant tabs.
They're probably talking about their experience on their hardware, we don't know what machine or what version of Firefox they're talking about. (It's possible it's a really old version and not really relevant now or it's possible their experience is valid for their hardware)
Well, I HATE having many tabs open. Just bookmark them for later. So far, FF is friendlier with how I go whereas the last times I tried Chrome, it often allocates RAM at launch for a thousand tabs that will never exist (hyperbole but you get it)