Persistent leg weakness following fusion surgery for severe stenosis

Hello - I'm a 56 yo male with two previous laminectomies in 1995 and 2014. My back problems were likely precipitated by a bad parachute landing in 1992. Up until this current situation I was active; daily gym, hiking, biking, and swimming.
Starting in Aug 2024 I noticed right leg hamstring weakness and foot drop with occasional trips and falls. However, I did not experience any back pain or sciatica. I went to a large Boston hospital for MRIs, CT /PET, X-Ray, biopsies, spinal taps and many other tests for MS, ALS, Guillain-Barre, viral infections etc, etc. The neurologists settled on a diagnosis of neurosarcodosis (lesions on lower thoracic and upper lumbar). The MRIs also showed severe lumbar stenosis but because I didn't have pain they focused on the former. I was progressively treated with oral steroids, IV high-dose steroids, oral methotextrate, and remicade infusions. Symptoms continued to worsen; increasingly difficult to go up/down stairs, more falls, my legs would seize/spasm, stopped driving and needed canes. By Sep 2025, I was using a walker half of the time. My neurologist consulted a neurosurgeon who advised surgery to address the stenosis. I had lumbar fusion surgery on Oct 21, 2025. I was in the hospital for one week post surgery followed by three weeks in-patient rehab at a skilled nursing facility.
After several weeks of at-home PT/OT I am now transitioning to out-patient.
My concern is that I have had minimal, if any, improvement post-surgery. In fact, I am still well behind where I was the day before surgery. I can walk maybe 15 to 20 feet with the walker before my right leg becomes unstable and I fall. I need a wheelchair the vast majority of the time. Stairs are currently out of the question. I need someone to put on/take off shoes and compression socks, as well as wipe my feet. I am unable to fully clean up after using the toilet. I have to shower sitting down. Luckily our condo allows one-floor living.

My neurosurgeon initially said it could take three to five months to get some recovery; he is now saying a year. The fact that I have improved so little is concerning to me, at least.

I would welcome any input from those who have similar diagnoses. What were the treatment(s) and the outcomes? Were any other courses of action taken that proved to be helpful? Thanks!