I’m not sure I understood the questions OP.
Falcon vs Wildcat would be a great fight. Not sure who would win though.
If the OP is asking for 2 individuals from different companies to have a battle to end all battles, I’d pit these characters against each other and grab the pop corn.
Wonder Woman vs Power Princess
Allen the Alien vs Doomsday
Blue Marvel vs Captain Atom
Thing vs Draaga
The Unmaker vs the Anti-Monitor
Lobo vs Battle Beast