In 2016, when Google implemented the Page Speed Update[1] 70% of global cellular network connections were at 3G speeds or slower[2].

In this context, I don't believe it was antithetical an an input for the best search results for searchers, the majority whom benefited from fast pages.

I can't find an updated stat for 2020 but I assume it's low enough that it is no longer makes sense as an input.

[1] https://developers.google.com/web/updates/2018/07/search-ads...

[2] https://www.thinkwithgoogle.com/marketing-strategies/app-and...