Hi, I have changed my sons surname.
It took me over a year to convince my ex to do so and I was only adding mine in to make it a double barrelled surname.
I had to get his consent and he, along with a witness had to sign the deed poll documents when they came through to make it official (to be sent to doctors, passport, banks etc)
legally you need consent and a signature to do this but I do know that you can apply to the family court to have this changed. Given your circumstances I can’t see that they would be entirely against this.
One option could be to have both of your surnames, his first and yours last without a ‘ – ‘ in between. Legally you then don’t need to use both surnames, only the last.
Min the meantime though, a better option for social media may be to change the surname. To something maybe completely unrelated.
Hope things work out for you. X