Come to think of it, I think that's going to be my daily driver again for all those reasons.
Older hardware and "tech", to me, is uniformly better in comparison to the latest and greatest nonsense that "web developers" want to push down the pike. All you want is to take more of my system resources and put them on the Internet. That's not acceptable to me in the slightest. Your "newest technology" is my newest horror and the reason I've most recently questioned the value of computers as a whole. Taking one iota of control away from the user is wrong. Giving the user a structure which can be 100% customized with emergent properties the developers might not have had the forethought to include is what all software with a UI of any kind should be looking to do. Simply put, you are not the NetHack Dev Team. You do not think of everything.
As I said, I don't use most of the features the browser includes. I don't care about them, and I know that I never will. The older I get, the more I see the value in the method Stallman uses of downloading a page, parsing it to clear out all the gunk, and then displaying it locally on a non-connected machine.
There's stuff in there I think is horrendous, like all the stuff for ECMAScript. There's stuff I like, such as the full choice of theme and function, the fact that my settings are mine - not yours, not Mozilla's, not Google's - mine. But I respect that it's got value to some people who want to turn it on. I'm not a person who's going to tell you what bleeding-edge new feature they're missing. I'm a person who can tell you that this program does a reliable and remarkably thorough job of displaying downloaded HTML in the way I desire to see it. It lacks any really good gopher or telnet support, but I cannot ask miracles.
My use-case is not the standard and I recognize that. You asked me a subjective question. I gave you a personal answer. And now you're telling me the only Internet-facing software I see being even marginally decent is 'Underwhelming'? Your seeming lack of understanding when it comes to the nature of real life is underwhelming to me. Try the software for yourself. If, after using it with an honest attempt, you prefer to be led by the nose by Google and its cronies, then by all means i cannot prevent you; nor would I want to. I'll lag back and wait to see the problems before they reach me.
In order to deal with a constrained environment I ran i3wm instead of a complex environment. I adjusted some scripts/configuration that seemed OK on a faster machine but sucked on the underpowered one. I autostarted almost nothing in the background. I kept it to a minimum of tabs.
The problem with running an old version of Firefox as a strategy to deal with an older machine is that older builds are actually slower and the tabs are in effect javascript applications that in fact do have all the defects you ascribe to them regardless of which Firefox they are running on.
Yes in many way the modern web is moronic. We don't even disagree. I just don't think windows + palemoon is a great strategy to deal with it.
If you want to really blow your mind either buy a $50 SSD or stop your antivirus "real time shields" from slowing down all filesystem access.
If you are force rebooting when you start it my best guess is that your intel atom with 2GB of ram is starving and thrashing.
The more them able ui is an artifact of sticking with older tech not specific work by Palemoon devs.
We are left with a front end for select settings in about:config and even less interesting extensions.
Underwhelming.