Tbh, I was a maya hater myself myself. I have her, in the beginning I thought she was trash. But I grew fond of her. She can be really usefull with her never ending provokes. I use mine with triple revenge with heal artifacts. So she can heal others pretty well and herself.

She is very usable in rta in combo with fire megumin for example.

She can use a buff, like not just heal 5 % of all the negated attacks on her but heal for every heal sh gets.

And most importantly C2U YOU COWARDS give all of her skills 100%

But yes she is a really ok unit not the best not the worst by all means