Ds question

Can you put the No$gba ds emulator into full screen?

With an addon, yes. Without an addon, no. [only applies to NDS games]

do u know where i can get the add-on?

Here:
https://www.romulation.org/forum/index.php?topic=1462.0[no$zoomer addon] - look for it in there

It can go up to a 3.0x ratio, which doesn't cover the screen completely, but will probably reach far out of it.

the 2x ratio is just fine for me