Anecdotal counter-point I have a colleague with a Samsung Galaxy Tab A 8" 2019 (SM-T290), and after just 3 years it became absolutely unusable, even after a factory reset. And it's "by design": it shipped with 2GB RAM, which was usable in Google/Android 9 (shipped OS), but just completely dead on Google/Android 11 (updated OS). Obviously I saved that device from oblivion with a Google-less Android that takes half as much RAM.
[1] This is improving greatly in the last year or two, but that probably wouldn't have made it to your chromebook.
The bus on these older model chromebook devices had a choking issue where the kernel would fully saturate the transfer bus and cause a cgroup scheduling strategy to give full priority to the processes using the bus at the expense of the gui. Solutions to this problem include a new NVME or software level cgroup reconfiguration of the kernel to revert scheduling priority to equal across all cgroups.
Or it could be something else entirely, but last time i had this issue and bug hunted it the finding was as stated above.
I also have a Lenovo Ideapad Chromebook running on an Intel 4020 with only 4GB. Despite being slow hardware, it runs circles around the Duet. The 4020 can be sluggish at times, but it never had the big slowdowns of the Duet. It could even run Visual Studio Code at acceptable speeds. Something was very wrong with the Duet. Usually Chrome OS is good on lower end hardware.