In an anime I heard the line
which was translated as "But we probably should head back. It's warmer inside". I know the ～ことは～ようが form, meaning "but" (like 「この薬は効くことは効くが、飲むと眠くなってしまう」), but I wasn't able to find the form with ようか, so I was wondering what's different: the AようがB form means "A, but B", while from that anime line AようかB seems to mean something like "But we should A, [since] B", but without having more examples it's just a wild guess.
Edit: The protagonists went outside to try a boomerang one of them gifted to the other; after trying it for a bit, one of them says the sentence I'm asking about, and starts heading inside.
Here I uploaded the audio, if anyone wants to check if I heard correctly.
Edit: more context: Adachi met Shimamura for the first time not long ago and they became friend; she's clearly in love with her, while at the moment Shimamura's feelings aren't so clear.
They spent Christmas together, then exchanged gifts: Adachi got a boomerang, so they head outside to try it. She isn't able to throw it very well (Shimamura's comment is いまいち), though she does some nice tries not having used one before, so Shimamura asks if she should buy something else and Adachi says she likes it. Then Shimamura acknowledges this (そう) and says the sentences I asked about.