I posted a link to the NASCAR 2021 car in another thread & given that Supercars and NASCAR have been in communication in recent years (although to be fair, they've been in touch with each other for nearly 20 years, just not making a big noise about it) I would be surprised if Supercars aren't at least looking at what NASCAR is doing and speaking to them about it.
If the new NASCAR engines were cost-effective it might make sense to go down that path and run commonality of drive lines. NASCAR could probably find out a fair bit from Supercars about the items on its new car that Supercars has existing experience with.
Interesting times ahead - but having said that, we can all speculate in here until some form of announcement is made but until then, it's all hypothetical.
OK - I'll go back into my Summer hibernation now!!