Resolution in the Begin Setting

[Resol]

Hi, in the beginning when i open "new project" a window pops up where i can set the resolution, standard is 1920x1080 set (see picture 1)
Do i have to change this to 2560x1440 if i want to make a 2560x1440 Video or is it enough to let it at 1920x1080 and just export it than in the exporting settings (see picture 2) as 2560x1440

I already know that i can also input videos from OBS or Pictures in 2560x1440 resolution BUT the important Question is if it will be scaled up from 1920x1080 to 2560x1440 if i dont set it at 2560x1440 in the beginning? Because a scaled up video from 1920x1080 to 2560x1440 will always be lower quality than original 2560x1440.

So if i set it to 1920x1080 in the beginning, than i input a obs video in 2560x1440 + pictures in 2560x1440, all works and i can export it in 2560x1440 BUT will VSDC now upscale it from 1920x1080 to 2560x1440 because i have set only 1920x1080 in the beginning?