Who is the most underrated character in Ramayana in your opinion?

Maybe Urmila.

She was away for 14 years from her husband as her husband decided to support his brother.

Kumbhkarana (rest all didn't care about who is right/ wrong apart from vibhishna), he knew very well that Ravana is wrong. Tried to correct him multiple times. But still stood for his brother side. Knowing he and ravana both will die by lord Rama's hands. I also liked Laxman (standing with his brother)

Inb4 Modiji get their name added in future iterations of Ramayana for building ram mandir

Kaikayi, mother of bharatha. She is the dark knight. Is she hadn't done what she had to do, nothing would have happened. Unfortunately, punished to this day. No kid ever got named kaikeyi.

Laxman, the og bro who got your back.