I think you guys are overthinking it
Just like Jay Nakamura is a stand-in for 5G Damian
Damian himself will likely be a stand in for 5G Luke fox(now jace fox)
I am certain that jace will exist in his own little universe and won’t be too important to future DC plans with Jon and Yara
And if he ever meets a Superman that clicks with him…it will be a mainline Val-Zod