Yes, easier on the joints.
Remember, the key is to get to within 1-2 reps of failure…no shit failure. Think of all the reps before the last really really hard 2-3 as reps that are just getting to where the good stuff actually happens.
Treadmill — I’m not a fan of people going from zero to running, as the tendons and ligaments in your legs have not yet adapted to running. I recommend non impact cardio, like stair stepped, elliptical, stationary bike, etc. I do 10-12min of stair stepper, lift for 45-60min, the 20min of stairs.
I also superset nearly everything, only taking about 1min rest between exercises, so the resistance training session is kinda cardio also. For example, one set of chest press, walk around the gym for about 45”, jump on pull up bar, walk 45” repeat. My gym is never very crowded when I go, so I can do this.
As your body and form adapts, pick 1-3x compound movements and focus on build strength for these moves.
A typical strength session is 3-5 sets of 3-5 reps, with complete rest between each set. And those 3-5 reps are very very heavy. Your sole goal is just put up as much weight as you can. However, you need to wait for these until your joints and other structures have adapted.
Finally, it’s very useful to have a monthly test that guides your training focus for 4wks. I’ve been focusing on pull-ups. Marine Corps age adjusted max pull-ups for 50+ is 18, tested yesterday at 19 and a shitty 20. Goal is 23 by end of March when I’m 58. 23 is USMC max, no age adjustment.
Anyway, it’s valuable to have objective metrics and goals to give you focus and to apply that focus in 4wk intervals, as this is a short enough period of time to guide you daily