I've been thinking about what a friendship between Penelope and Cressida would look like.
Imagine if, instead of being the Bridgerton's neightbors, the featheringtons lived next to the Cowpers.
Like at first it would be horrible for Pen, I don't think ske would have become as close to Eloïse as she was canonically. In their childhood Cressida would have probably joined Pen's sisters in their bullyinh of Pen BUT at some point I feel like some kind of understanding would have come for both of them.
Like Philipa and Prudence are mean but also really dumb and Cressida would have grow exasperated of them and would have reconize that Pen was the smarter one betwenn all the featherington's sisters. Cressida already pay more attention to Pen that Eloïse (notice how in s3e4 we learn that Cressida noticed the crush Pen had on Colin).
And I think Pen would have noticed the way Cressida's parents treat her at some point.
I can see a complicated but none the less sincere friendship between the two of them. Cressida would have catch on Pen being lady whistledown a lot sooner too.