Currently it is possible to do Remote Play of PS5 on PC, Android/iOS and now apparently also on PS4 (for some reason)
I doubt Sony will mind making the PS5 compatible with the PS Vita in the future (even though it is capable of remote play with the PS3 and PS4)
Is there a way to do a homebrew or even change the PS4 Remote Play app on Vita to connect with the PS5?