As everyone else is saying, the scrolling feature itself seems to be randomized in the main menu.
Any input seems to be given just a random value (up, down, left, right, and left click).
Mouse input, WASD, and native arrow keys all seem to just GIVE you a random input while SHOWING you the desired input.
Kinda weird but it effectively makes selecting anything impossible, as it isn't "technically" selected as the menu shows you via highlight.
Seems to be fine on re-launching the game, but after a match (finished or leaving early), the menu breaks again.
Reading around, it seems like this would be a possible cause.
[BFComms] Battle Pass Tier Skipping with Winter Offensive Bonus Path | EA Forums - 13003008
I guess the optomized path to getting the mode you want, every time, is to:
1: start game
2: immediately pick your desired mode
3: click start (so that when you go back to the main menu home screen you can just click Lobby and start from there
