Option to give more time to opponent in zen mode

Hi, I'd like to ask for a feature.
I couldn't find any thread in this, so sorry if it's already answered.
I like to have the option to give more time to the opponent. I don't use it most games, but sometimes the position is so interesting that it is a pity to win on time.
I also like to play on zen mode, but the option to give more time to the opponent doesn't appear.
I don't think it would substract anything from zen mode to add it, so could you please do it?
Thank you very much.

Hi!

The Lichess API provides the possibility to give time to an opponent,
so if you know how to use "curl" for instance, you could prepare a script to do this!
The API is documented at lichess.org/api#tag/Challenges/operation/roundAddTime

Here's an example of a simplistic GUI application,
using Java library "chariot", to make it easy to give time to opponent - gist.github.com/tors42/aa9e36aac0ddc56f3ec2ac5cc88d9930

Chess on!