I googled and found this link with the word “materteral”.
www.grammarphobia.com/blog/2006/08/female-version-of-avuncular.html
And this link which suggests using the Latin "amita" as a starting point/root.
english.stackexchange.com/questions/58383/is-there-a-feminine-equivalent-to-the-adjective-avuncular
I'm an aunt, (a bloody terrific one, if I do say so myself
) and I would like an actual, recognized word that means "aunt-like". Any ideas?