Looking to buy likely my last bike - advice sought
At 58.5, I'm in a position to rearrange my bicycle situation and am in need of some advice as I've been riding mostly recreationally on my Jamis Coda with my wife and teen for a few years and am no longer "up" on that's current in the bike world. I'll be a brief as I can.
Selling: Jamis Aurora, `1973 or 4 Fuji S10S, 1978 Fuji S12S and MAYBE a Jamis Coda.
Me: Clydesdale, heart in good shape, back suffering from disc issues from an auto accident that also broke 3 vertebrae in my neck, knees that are going to have to be replaced in a few years.
Goal: Find a stiff bike, stiffness like a steel touring frame that is NOT a drop bar bike. The handle bars on the Coda with a tall stem really feel good. OR modify/upgrade the 2019 Coda into a better version of itself. The issue there is that I don't thing the Coda would ever make a good gravel path bike. Do NOT want a battery involved bike. Really need ride comfort but because the doc said I have two basic exercise choices, bike or swim, and I chose bike, I need a cycle that will give me quality exercise without "breaking" my back.
Considerations: Fat tires are more comfortable for my spine, but not so much so that they are a hard need, and the weight of that kind of bike makes the decision difficult. Honestly, I think that whole question (fat/heavy vs thinner/lighter) is about a wash for me.
I've looked at the Kona Sutra LTD, Surly Ogre and Surly Bridge Club but am not tied to any course of action. As this will hopefully be the bike that takes me to retirement and beyond, even Rivendell would even be a consideration. They aren't doing custom orders though, they're backed up 2 years at present and I can't wait that long.
Recommendations?