There are certainly examples of relatively muscular vegans, but most of them aren’t particularly strong. They’re simply strong relative to their bodyweight. And they’re not necessarily life-time vegans. It’s very difficult to accumulate new muscle on a vegan diet, but not as hard to maintain it. Most have pretty good health metrics though (blood pressure, cholesterol, etc.).
I don’t think a vegan diet is a bad temporary solution for someone who is obese, as the OP is. I have yet to meet someone who was overweight, switched to a legit vegan diet, and stayed overweight. I would see nothing wrong with doing this to kick off the OP’s diet, since he’s so significantly overweight. He could get down to that 15ish % bodyfat level, and then re-introduce lean meats to begin to add muscle to his frame. There are worse approaches out there.
Whatever approach the OP takes, I believe fat loss must be the initial priority. Everything will be easier if he works from that point.