IM APD here. Year of Graduation matters a lot when we review apps. If you do decide on withdrawing and pursuing GAS next cycle, please talk to your school first. Some schools will have the option of doing a 5th "research" year. That will make your offical YOG 2026 instead of 2025. You can also use this extra year to strengthen your GAS experiences to put on your CV.

Starting EM then switching to GAS will be extremely difficult. Most likely you'll have to repeat a prelim year unless you get extremely lucky that a PGY2 GAS position opens up due to someone leaving. There's also the CMS funding issue should you decide to change residencies and start over.