1) you don't file SC taxes unless you earned income in SC outside of your military pay...i.e only if you moonlighted in a civilian job in SC, or got some income for property you owned in SC, or did off-duty self-employment work in SC.. IF none of those exist, then your error was in the My Info section where you might have said you "moved" from SC to some other state in 2019. For tax purposes, your only possible (maybe) "Move" was from VA to FL .
2) I can't see how you could declare yourself as a FL resident. As a military member, You have to actually be posted to FL in order to do that, and the Military Personnel/Payroll office must accept your DD2058 making the change. They are unlikely to do so unless you were PCS posted to FL...and you haven't mentioned that (yet). ( AND, the ability to claim a spouse's HOR under MSRRA is only available to the Civilian spouse of a military person....not to either spouse if both are in service (((though, I guess I need to double-check that))).
3) Thus, absent the VA-FL "move" .... You should have indicated in the My Info section that you lived in VA all year, and did not move anywhere . (If you do somehow have a valid change to a FL state of legal residence (SLR), then you would indicate a "move" from VA to FL on the date your DD2058 was accepted...and then be required to file a part-year VA tax return for all income before the "move" ).
No SC tax return is needed without actual SC income.....unless you have a civilian spouse who worked in SC during 2019...then it depends on what SLR he/she claims),
____________*Answers are correct to the best of my knowledge when posted, but should not be considered to be legal or official tax advice.*
