Unity version generally doesn’t matter when doing most VRM stuff. You can usually use the version VRChat currently requires.
Import VRM, hana tool to add clips, adjust materials/outlines
VRM - mtoon, blendshapeclips, vrm first person/eye tracking
Unity, import VRM, VRM paramaters, mtoon shader, blendshapeclips, dynamic bone to springbone for attachments, vseeface sdk, pasha sdk, export VRM/vseeavatar
Unity, import VRM, hanatool to add stock blendshapes, export VRM
Export VRM, upload to cluster, seedonline, vroidhub, dmmvrconnect, and stick it in google drive