Shoutout to FlyingFox for the info, btw
https://discord.com/channels/447620435744522253/788551945065201675/856705448799240263
from Kasumi's post in sonic-2-2013 but slightly changed it
There's an alternative shorter way to get s+t and elemental shields in time attack mode without having to game over:
With dev menu on: 1-Select time attack mode, select green hill 1 2- press f2 once, it will take you to level select 3-go to player and select 00 for s+t and go to items and select shields 4- press f3 to go forward the stages and go to the act you want, it will be on time attack mode
From the settings.ini see : https://wiki.libsdl.org/SDL_GameControllerButton and you should be abl eto figure it out. I have mapped my PS4 controller based off of this