I've been buying old flagship phones and they seem to last a while. I got the S9 for under $300 NZD and its still going even with no security updates. I then got the S10 for some family and thats still going good.
If you want a cheap phone 2nd hand refurbished versions of good phones are in my opinion the best way to go.
Do you have a link to the post and the replies you found toxic? So we can judge properly?