Simple problem, simple advice:
1.) You want to become a TL in GM.
2.) You want to date a GM-TM now and after you become a GM-TL.
3.) Company policy forbids leaders dating subordinates.
4.) Your SD doesn’t approve of any form of TM dating.
Therefore, you can either (continue trying to) become a TL or date the TM. Here’s a chance to use one of those skills that are necessary for leadership: prioritize. You can choose either your possible promotion or your dating life, but you can’t have both, not at Spot, anyway.
In case you think it’s possible to get promoted and date one of your team members on the sly without anyone finding out about it, that is a pipe dream. Stores are full of bored staff members doing repetitive tasks and looking for a little excitement or gossip to relieve that boredom. Sooner or later one of them will see a look, some body language, a “secret“ meeting or overhear a conversation, and the store grapevine will light up like a Christmas tree, providing the team with a lot of entertainment and you with a lot of misery. Seen it happen several times, and it doesn’t turn out well. Just saying.