Gfyuki

Would using a hair removal cream on one's face (such as Nair) be in violation of rounding the corners of one's beard? (Vayikra 19:27)

Namely, would it be akin to use a razor (assur) OR more akin to using a scissor (likely mutar)?

It is permitted to use depilatory cream (but not on Shabbat).

R Jack Abramowitz writes

The Torah only prohibits using a razor to cut the corners of the
beard. There are five such corners and many positions when it comes to
the details, so a pious person should not use a razor on any part of
his beard, nor even on his mustache or on his neck. There is no
difference between an actual razor and a sharp stone that cuts hair:
they are equally prohibited. Those who remove their beard using a
depilatory cream must be careful not to scrape the cream off with a
knife, as that might cut the hair. Instead, they should use something
like a wooden chip.

Similarly R Joshua Maroof writes

In the olden days, men who were clean shaven typically used depilatory
creams to achieve that look. This involves no prohibition because it
is not considered shaving.