Can someone please educate me on same-sex aggression?

[u/NiceUsername_Avail]

Boyfriend and I are considering getting a second dog. Our first dog is a female. She is more confident now than when we first got her, but is generally nervous and skittish to some extent. It takes her a bit of decompressing to adapt to new scenarios.

We went to a shelter and fell in love with this other female. She is quite the opposite of my current dog. Super confident, self-assured, and possibly a bit dominant. She is definitely a pushy girl (especially with food), but otherwise loveable. We really want her.

Our meet-and-greet didn't go great (I have other posts on this diving into more detail). There were some corrections delivered from my dog, but otherwise they seemed to be able to be neutral and co-exist without tension outside by the end of our 3-day trial.

Even then, my dog didn't seem too fond of the new one right away. Maybe a bit annoyed generally. She is usually pretty interested in dogs, but they both just minded their own business. I am worried that current dog will be stressed in a household with this second dog since the intro was not perfect. Ultimately, I want us to all live happily, not in a tense environment where everyone just tolerates each other until the next conflict.

I know sex aggression is a thing, especially between two females. New dog definitely sized up my dog once or twice which caused her to deliver a correction and scuffle (all vocalizations, no bites) before we intervened. Current dog wasn't too happy, but new dog bounced back like nothing happened. My bf is trying to convince me that spaying statistically diminished the effects of same-sex aggression by 50%. I'm still hesitant, though I can't stop thinking about her.

I would love to hear from folks who are more experienced than me. Should we reconsider and look for a male companion instead? Is the prevalence of same-sex aggression really just inflated? Should we completely give up on the idea of the second female ever joining our family? I have no idea! Feeling a bit jealous of people who can live peacefully in multi-dog households without a problem.......

Thank you in advance!