I’ve toured many times on several different bikes. In my exexperience a comfy frame unloaded does not make a good touring bike when fully loaded, they flex too much. I now have a Surly long haul trucker, unloaded it feels harsh and stiff, but put some panniers on it and it is really comfy, the heavier the load the better it feels.
I am not exactly someone who packs light. So even for short trips I will have 4 panniers, a bar bag and tent on top of rear rack. To some people this may feel over the top. But I find that carrying extra kit and the weight penalty is more than worth it.
Once loaded i find that adding an extra 5 to 10kg of extra kit isn’t that much more noticeable even up big steep climbs.