There is good reason for hope in your situation, seems they caught it fairly early. Mine was not Dx'd for about a decade despite seeing 3 PCs, a cardiologist, a rheumatologist, 2 neurologists, 3 gynecologists, a carpal tunnel specialist, and 10 weeks of occupational and physical therapy with surgery scheduled for carpal tunnel. I left that clinic (TVC in Vancouver Wa) at that point and went to MDVIP. Dx'd first day there. I've made good improvements but the damage was too much. I'll never be able to rollerskate worth a💩again, which is my happy place, my blood pressure and heart rates are both in the stratosphere from autonomic damage. Balance is effed up. Walk like I'm drunk all the time. Might have to give up motorcycle and quad riding, my other happy places. Just too painful and a little dangerous bc of balance and weakness issues from the deficiency.

You're gonna get much better maybe even 100% better but don't EVER stop the b12 treatments you'll have to be on for the rest of your life. Also research folate (helpful) and be wary of b3 and b6-- do not get to much of those. If you're really really brave there is a supplement called lions mane that is supposed to help repair nerve damage, just do your research and get good quality non- contaminated lions mane.
Best of luck to you my fellow b12 warrior.