My mom is taking over and making our wedding about her

She sounds like a narcissist, and I'm sorry. My mother is one.

Unfortunately for you, I solved this problem by offending her selfishness to the point where she hasn't spoken to us since she received the invitation, and did not come to the wedding. (This made our wedding day much better.)

Honestly?

Assign one of your BP to be "MOB wrangler". That means distracting her whenever she tries to take over, interrupt her when she starts to get mean, and basically be a pest to her to keep her off of YOU.

This! Typically parents leave after family formals and over. The couple portraits are of just the two of you. I would possibly let your photographer know that you want her dismissed so they can reinforce it when formals are done so she can get the not-so-subtle hint.

I'd tell all the vendors and even bartender that your mother might try to pull rank as MOB & get them to change plans. Give them support to say "that's not what the bride and groom want". They are professionals and more use to this than you, but good to point her out just in case. I also second a bridesmaid or her husband to run interference. Best wishes, Bride.

Agreed with Rebecca on enlisting someone who is willing to intercept her if necessary.

Also let the vendors in on it.

It's uncomfortable, but my husband and I were videographers at a wedding where we were told ahead of time that the father of the bride would likely try to commandeer things and boss us around, and so when the time came (and it did) we politely said "thank you, but we already have our instructions. If you have any concerns, I suggest you talk to the wedding planner."

If you don't have a wedding planner, default again to your BP/MOH/whoever will stand up to her. Definitely appoint someone to intercept her before she gets to you. Vendors should be informed of who this person is, too. They will handle it their own way, but make sure they have a middle man to direct her to - she may still bypass that person, but the effort should be made to keep her away from you.