Using DX12 compared with the DX11 version of the game the game has better frames, between 10-15 more, and a more stable framerate.

Mouse input lag feels better.
Also, using Nvidia's Reflex setting on Boosted is stable now. I remember framerate going crazy back then.

Vram use increases, but in my opinion, now is using what always should be using according to the Video texture pool setting (Low, Medium, High, Very High, Insane).

Ofcourse, all this improvements depends of your PC. You may have better results in a modern hardware rig. Give it a try anyways.

Go to Apex properties in your library. And add this command in your launch settings.

EDIT 5/7/24
-eac_launcher_settings SettingsDX12.json OLD!

For the new version of the game, in order to work it changes to:

-anticheat_settings=SettingsDX12.json

EA Game Update Changelog

Thanks @Vitryol

If you want to skip the game's intro use this command too

-dev

If you have the main menu locked to 60fps and you want to uncap it, use this command in the game's launch options

+fps_max 0