I am playing a campaign with a few friends and we are all kinda new including the DM, though he does have a little more experience than the players. The other day the DM asked everyone for their character's backstory, offering to help people come up with more details if they wanted to but otherwise leaving it up to the player.
The character I am playing is an anime trope I thought would be fun to play in a D&D game, everyone agreed it'd be fun and that these aren't often played if ever (according to our extensive research as internet dwellers).
As I struggle to have time between work to properly write my character's backstory and send it, the DM and I kept texting back and forth and he would offer up scenarios he thought would match my character, most of them stuff I had already thought about and had decided were in my character's backstory.
At this point I thought we were on the same page.
When I finally get a day off I type everything up. I believe my backstory is original because I haven't seen it in any anime before. It was great, it made sense with the character, and it had the potential to be both simple or very emotional and heartstring pulling, depending on what the DM decided to do with it.
5 minutes after I sent the DM my backstory he sends me a lengthy text telling me how he doesn't like it and is changing pretty much everything, ignoring half of it and letting me know how mediocre he thinks the parts he's letting stay are. All with a tone of "I don't like it because don't think its original."
I don't know if maybe I didn't choose the right words to get the message across or if he just made my character's backstory all on their own and planned to shut down my idea regardless, while still telling me I got to do it myself.
I don't like this version of my backstory; it changes a lot of my characters core beliefs and I won't know how to play them anymore.
I don't know what to do as both of us are creative minds and are attached to our ideas. I don't want the DM to give me a backstory I don't like, but with the character like this, I won't have fun. I also don't necessarily want to tell him how to do his job.
What techniques or ways are available to resolve this?