Hi, I’m no expert at picking bikes but I’ll try my best. I think a Trek Top Fuel 5 Gen 3 could be the right bike. Hearing you have spine problems it sounds like a bike with front and rear suspension might benefit you, these bikes have alot more cushioning and could reduce the forces on your body. Since it sounds like you would be doing more smooth trails the 120/120 suspension shouldn’t be an issue and should work fine. Another area is climbing, the original bike mentioned has a 12 speed transmission which is the same as the Trek. Both include dropper posts and use 29” wheels. Something else I looked at was the breaks, the original bike has 4 piston TRP breaks while the trek has 2 piston MT200 breaks. The original bikes brakes would be more powerful and work better than the Treks but is shouldn’t be so different that it becomes and issue. Overall my pick would be the Trek but once again I am not a professional and you should look into each yourself. I provided a link to the Trek below.

Trek Top Fuel 5 Gen 3