I'd probably choose Sword, because I usually choose the 1st version over the 2nd version, and red's my favourite color.
If I had a Pokemon game collection, it'll probably be like this:
• Red
• Gold
• Ruby
• FireRed
• Diamond
• HeartGold
• Black
• Black 2
• X
• Omega Ruby
• Sun
• Ultra Sun
• Let's Go, Pikachu!
• Sword
• ??? (Gen 9)
• ??? (Gen 10)