Yesterday I had a hanging browser without full crash but an error message regarding booster-browser - wait or abort. I did nothing to not confuse the phone and only waited, and luckily the browser continued after abt. 5 seconds.
most crashes or at least massive delays occur on this SFOS Forum site, fewer on news.orf.at , surprisingly Youtube never crashes.
Strange, why is booster-browser listed twice with different PIDs?
thatās above my knowledge
My too, but looks strange. Right now I had my first crash on sending a SMS. So maybe the underlying problem is really not the browser itself but more the process management in base system. There I can also say nothing to it, imy knowledge is much too less.
Maybe this is a kind of a bad joke/trolling:
Strange, why is booster-browser listed twice with different PIDs?
To boost it twice as fast! 
Booster browser is a systemd template service (booster-browser@.service).
There are at least two services derived from that template, one for the browser and one for the email apps. (In theory any app which uses WebView could have its own booster this way.)
Each has their own booster process, the same binary with different configurations applied.
Profiling
Has anyone in this thread poked around about:memory screen? Anything noteworthy?
Yes, now. Because of your information that this exists.
I clicked āFree memory - Minimizeā¦ā, then enabled āShow memory reports - verboseā and clicked āMeasureā.
A strange output is this (maybe of interest):
Warning: the āheap-allocatedā memory reporter does not work for this platform and/or configuration. This means that āheap-unclassifiedā is not shown and the āexplicitā tree shows less memory than it should.
I honor this efforts to get a more stable browsing-experience but i fear the solutions will only last until next update of the used Browser-Engine in native SailfishOS-Browser.
So weāll have plenty of time! 
What make you sure, did there exist some kind of a Roadmap for the Updates?
Roadmap? Nothing is sure. Ask Jolla for roadmap and tell me!
edit: I extrapolated the Browser update intervals from 2019 until today.
They are waiting for something to be stable enough to release a new update, I donāt remember what but Iāve heard from Jolla something
Just for info, I continued my experiments with the browser and set all āgeneral.smoothScroll.*ā settings to false. This speeds up browser significantly, and I did the same settings change also on laptop and also got better browser performance there.
BTW, on my XA2, browser crashing due to low memory is quite a problem. With only the browser open, it still crashes and force closes 
I could also minimize browser crashes by letting another app run that keeps CPU busy and prevents the phone from entering some power saving states. Usually I let DeadBeef Silica play music or AllRadio play webradio. If I donāt want to listen to music I turn volume down, but keeping the CPU alive minimizes browser crashes on my phone.
That makes me think to disable battery saving mode and to only activate it from 20%, right now i activate it at 79%
I noticed the sites that went blank at scrolling are not blanking anymore with ap.touch.start tolerance set to 0.0762785 (without f)
Iām on Xperia 10 ii with sfos 4.5.0.19