Berdly and Kris not actually having gaming duels despite prior chapters mentioning "he only gets this mad when you play games together" seems to be a strange retcon or contradiction, but upon inspection we can see there may be a little more going on here.
The games mentioned throughout Deltarune include Dragon Blazers, Minecrap, Smashing Fighters, Roblucks, and an unnamed racing game that Noelle and Berdly play together (plus any others I may have missed).
The games in which you specifically partake in "gamer duels", or pvp, include Smashing Fighters and the racing game, which leaves the semi-linear rpg or sandbox types.
We know that the "prank caller" from Noelle's blog story is almost certainly Kris. Thus, at least the Minecraft pastiche is one of the games the two of them play together, leading to an interesting recontextualization of the gamer relationship between Kris and Berdly: