Is there a tracker native to gamegear?
I've tried looking through a few threads on here, but there's never any on-point answers.
I saw mod2psg2 or something on here, but it seems that just emulates the gamegear's sounds.
nothing native, you can use the program you mentioned to make files you can play on a flashcart on real hardware, or use little scales midi interface.
GameGear sound is the Sega Master System's SN76489 with 0x06 register added to achieve simple stereo capabilities.
You could use DefleMask Tracker to make music for the SN76489, an update is coming soon that will include ROM export for Game Gear and stereo expansion for the SN76489.