I’m 79 yrs old…..off prednisone almost 3 months and I’m still on Kevzara. Stamina is hard to come by….I work at it everyday, for a few to several times a day. I.e., walk 2+ miles, swim, pool walk, lt exercise, heavy housework, etc.
Sorry to be the bearer of the news……it does get better but takes time. The hotter the temps the harder for me too.
There are days of significant break thru to keep me going.

Hang in there