How to exclude only the root directory

Hello, I want exclude from cache only the root of the domain:

https://domain.com and https://domain.com/

I can’t make it work, I try with:

^/$
and
^$

but don’t work, these or exclude ALL or not exclude the /

It’s clear what need I do ? I need disable caching for the root domain with / and without

but not to all the pages.