Why does T increase libido but E doesn’t?

There is a chance I do not fully understand the effects Estrogen has (I am more educated on T), so please take my question with a grain of salt.

Why is it that HRT Testosterone increases horniness, but HRT Estrogen doesnt? Wouldn’t it make sense for them both to increase it, because theres a spike of hormones in your body? I’ve dated a transgender woman in the past and she told me that since she has been on estrogen, her sex drive has been a lot lower, but maybe that is just how it happened to her. I am sure it’s different for everyone. I’ve heard a lot of stories about transgender men being super horny because of HRT, but not transgender women?? But when people assign female at being born hit puberty as teens, they experience spikes in libido like assign male at birth??? Is there a science behind this or do I just not understand estrogen>!?!<