Your first suggestion for that Acer CB- 311 is great price if a 5 yr. EOL is OK for Byrna, would not be with me:

"The Acer - Chromebook 311 with the Intel Celeron N4500 and 64GB eMMC will receive automatic software and security updates until June 2031. After this Auto Update Expiration (AUE) date, the laptop will still function but will no longer receive new OS or security updates."

I would expect 10 yrs. on such a device, but we all know that we will never ever see that from Google.

I am still using my late 2014 Mac Mini desktop, mostly thanks to Chrome that kept updating, being secure there, but recently had its' last update for MacOS 12, so I switched to Firefox, still supporting it. For how long, I am not sure, but I have either conversion plans, or a Chromebox may in my future, since Amazon's secure Lockers are nearby.