The first Digimon game I remember playing was Digimon World 4, and the second one was Digimon World: Data Squad. I remember playing as Dorumon in the former game, and not getting that far in the latter game, though I saw my brother get way further into the game than me.
I got DW1 and DW3 on the same day, but I didn’t understand how 1 worked, so I grew much more attached to 3. I eventually came back and beat 1 after getting used to the similar mechanics in re:digitize, but 3 will always be my original.