[Tepix]

A Raspberry Pi 1 with 256MB works very well with Pi-hole. It has a lot of free RAM to spare.

I think your posts underlines an important fact: Nowadays more and more tasks require an up-to-date internet browser. These browsers need a lot of RAM. Both their complexity and the websites' is increasing all the time.

[selfhoster11]

Works with Pi-hole as a server, or as a web client? If the latter, I will vehemently disagree. Raspberry Pi 1 was slow with native apps during the time it was released, to use it with the modern web would be painful.