Veronica or Betty. There was a subsequent storyline in which Valerie took the walk down Memory Lane not long after she and her family moves to Riverdale and imagines her life as Archie's spouse.
There is already a gay male character in the Archie comics universe in Kevin Keller, so it stands to reason that we could play the 'what if' scenario with these iconic characters in Betty and Veronica.
So it's not inconceivable to envision a scenario in which both of them get together one night and have the epiphany that their friendship has a deep romantic component to it that eventually leads to them kicking Archie to the curb and exclusively dating and marrying each other.
It would be interesting to see how both Betty and Veronica's families handle their relationship and eventual marriage, It would also be cool to see how they handle being a married couple in Riverdale and the ripple effects from it.
And yes, while Betty is and can be as glamorous as Veronica, Betty does know what tools are for and has a demonstrated ability to work on cars.
There would also be other ripple effect that would be revealed as their interesting 'what if' relationship progressed and developed.
And as a longtime Archie Comics fan I'd love to see someone tackle it.