Is it okay to say "See you next time" to an idol at a fan meeting?

When saying goodbye to an idol you first met at a fan meeting, is it appropriate to say "다음에 보자" or would "다음에 봐요" be better? In Korean etiquette, "다음에 보자" can be considered a bit casual, so I heard that a polite expression is important, especially to someone you respect. Therefore, I am debating whether phrases like "다음에 봐요" or "다음에 만나요" would be better. Also, I'm curious if it is appropriate to say "수고했어요" when the fan meeting ends. In Korea, it is said that this expression is used in a friendly manner, but I'm not sure if it aligns with the etiquette between fans and idols. If you have any experience or advice, please share. Thank you!