Used DM in conversation must follow "to" " for". DM to order, DM to me, DM for order.
sorry buddy, you're wrong.

It’s a transitive verb. verbs need an object. If you add
“to” it turns into a noun phrase, so you have to change the phrase into
"send DM to me" (DM become noun, send is a verb)
if you didn't change the phrase, just like
"DM to me" it's awkward buddy, there's no native using that phrase.
so,
DM me was like
"text me, follow me, email me, tell me" no need to add "to"
i thought that you were gonna point out
“u re”, because that's the actual mistake.
hope that makes it clear.
have a great weekend, all