Should I do a Supplemental Claim?

I posted a couple weeks ago about being excited of my increase to 90%. When I read through my Letter, I noticed something missing. I was claiming my left hip issues secondary to my Right Hip, Left and Right Knees, and Back. There was only mentioning of the Right Hip in the explanation of the denial. Below from my decision letter.

Service connection may be granted for a disease or injury which resulted from a service-connected disability or was aggravated thereby. The evidence does not show that left hip strain is related to the service-connected condition of right hip trochanteric bursitis, limitation of flexion (previously rated under DC 5019), nor is there any evidence of this disability during military service. (38 CFR 3.303, 38 CFR 3.304, 38 CFR 3.310)

The conditions of Left hip bursitis and Right hip trochanter bursitis are not medically related. The Left hip bursitis is a separate entity entirely from the Right hip trochanter bursitis and unrelated to it. A thorough review of medical literature failed to demonstrate a causal relationship. A nexus has not been established.

I am not sure if this was partially due to what I put in the claim or how I was trying to claim the left hip issues. Below from my claim.

Question 16: Claim Information Row 8 Current Disability(ies): bursitis in hip, left Exposure Event: My condition was caused by an injury or exposure during my military service. Explanation of Service Relation: Caused by an in-service event, injury, or exposure Secondary to Right Hip Trochanteric Bursitis, Limitation Of Flexion (Previously Rated Under DC 5019) My pain in my left hip is due to my body compensating the disabilities in my right hip, right knee and left knee by increasing strain on the muscles on joints.

I had put my claim as "bursitis in hip, left". Below from the decision letter.

Favorable Findings identified in this decision: You have been diagnosed with a disability. Your VA examination dated March 5, 2025 shows a diagnosis of a left hip strain.

My main question is should I or am I able to file a supplemental claim trying to explain that I should have filed for left hip strain and my intention was for it to be secondary to all of my lower biomechanical/musculoskeletal issues from my service connected lower back, both knees and right hip?

I only use the VA for my medical, and don't know how to get a nexus letter from a doctor outside of the VA. A VA doctor did tell me that my left hip is due to the other issues but my doctors at the VA will not write Nexus Letters

I am currently at 93% and if I am rated at 10% for this, then with it being bilateral, it might just put me at 95%. The back pay would be from March 2024.

A side note: I have submitted an intent to file a couple weeks ago, getting ready to file for IBS and an increase for right shoulder. Also, for GERD and ED both secondary to my medications for MDD/PTSD. I know most likely they might try to re-evaluate my MH, but that has worsened over the past couple years as well. I have my therapy appointments starting back up in a couple weeks. Going to do this in tangent with the Supplemental Claim in case that is still denied.

Any advise or help will be greatly appreciated.