and obligatory disclaimer: i am absolutely not saying that thinking you're trans at one point and then going "nope nevermind i think i just id with my agab" makes you evil. i have friends and mutuals who fall under that category and their experiences have actually made them more sympathetic to trans people instead of less. i am not saying that changing your mind and going back to iding with your agab makes you a bad person, i think it's great that you had the opportunity to explore your gender.
it DOES however make you cis and it means that while you may feel some kinship with trans people, you yourself are not trans and you need to realize that cis society is going to prioritize your voice over ours. you can use this as a great way to be an ally, but unfortunately because these people are still cis and just as capable of transphobia as any other cis person, you will often see them speak over us and claim to know more about being trans than we do.
people who detransition for safety reasons but dont id with their agab (or only id partially with it) are still trans though and not really who im talking about here because honestly most of the ones ive known don't call themselves "detrans".