TBH, that doesn't surprise me at all.
It's a well-known and, by now, simply "accepted" fact of life that web-browsers just do seem to "balloon" in size as the releases roll past.
I was using Chrome/Chromium releases in the high 20s/low 30s when I first started with Puppy over 6 ½ yrs ago. On the much older and less-capable hardware I was using back then, those browsers were still quite sprightly & fast. As the years rolled by, the browsers got heavier & heavier, and the hardware began to struggle with them. Now I've updated to far newer & much more capable hardware, I've just about regained the speed I used to have with the older hardware running older browser versions....
What does that tell you..? 
I use Sailor's 571 myself. And I run 'current' clones on it! Considering that no Chromium derivative beyond the high 50s will run on it natively, you may wonder how I manage it?
Simple. I cheat! I'm not really running it in 571 at all, but inside Tahrpup....as a chrooted 'jail', essentially running one Puppy from inside another. This is not exactly a feasible proposition for those of you with severe hardware constraints - the resource requirements become quite high.....but on this new HP desktop, I've got so much RAM & storage it's simply ridiculous. It doesn't even get noticed, and gKrellM barely registers what RAM it does use. I could run anything I wanted - even Redmond's abortion, I guess! 
- but I stick with Puppy 'cos I love its 'ethos', sheer flexibility & quirky nature.
The chroot 'jail' concept in use here is all thanks to @watchdog, of course. 'Jails' have been around for a long time, but watchdog was, to the best of my knowledge, one of the first Puppians to really start using one regularly and, more importantly, to 'share' that knowledge with the community. You can run mainstream distros as a chroot jail, but they need a fair bit of stripping, since they're so much bigger; Puppy, of course, is small and neat enough to simply use for a chroot jail as-is. I even put together a package of the entire Tahrpup 'jail' + browser, which you can load as an SFS, as & when you want it.....but you DO need around 1100 MB in total for just this item (when loaded). And that's in addition to the space the 'host' Puppy itself needs to run and function, along with anything else you might be running at the same time. Much under 2 GB RAM, and I feel you'd be on a hiding to nothing...
I also run a Xenial64 'jail' for certain applications in the 'lite' spin on BK's original 64-bit Quirky April 7.0.1 which @jrb assembled, and which has for some time been my 'daily driver'. It lets me run Zoom, for example.... 
Mike. 
thanks 
... I am going to retry after finishing to write here)
, and chromium doesn't eat too much CPU while I edit this