@kensanata My #SearchFu pays off.

"How did the romans trim their toenails" isn't specifically the scope of the question, but does turn up numerous informative results:

https://duckduckgo.com/?q=how+did+romans+trim+toenails&ia=web

("anthropology nail trimming" was ... spectacularly unproductive.)

Two of the better (still not great):

Tedium at least cites texts, including the Bible. Knives seemed in common use:
https://tedium.co/2017/02/07/fingernail-trimming-history/

Not very authoritative, though methods are mentioned: "How Did People Trim and Maintain Their Nails in Medieval Times?"
https://about-history.com/how-did-people-trim-and-maintain-their-nails-in-medieval-times/