Although two sessions of lifting heavy with a progressive overload gradually getting towards failure (as you get more experienced) will build muscle.
But not with 2kg dumbbells!!
Some PT sessions will pay for themselves in tne long run in the knowledge and confidence you’ll gain. Talk to a PT NOT about losing weight, but about learning the major compound lifts to build strength.
Learn how to lift with a barbell. Learn to do aback squat, a deadlift, a bench press and an overhead press. Start with just the bar. It weighs 20 kilos. Then work on progressive overload. Think about it over a year of this and keep adding a small amount of weight each fortnight or so.
Also work with a PT on an interval training pattern. You can start with 45 seconds on going as hard/fast as you can, 15 seconds off. You can run, do a SkiErg, burpees, row, whatever. But you should work at about 8-0 RPE (rate of perceived effort) each time.
Over 2 x 1 hour sessions maybe plan your sessions like this (others will make other suggestions)
Day 1
warm up by doing your treadmill walking but just get warm.
Then do back squats and maybe lat pull downs. Do 5 sets of each exercise (after a warm up set of just the bar), with 6-8 reps in each set. As you get a heavier barbell, you can do fewer reps. The final 2 reps of each set should puff you out. Rest for 2 minutes between each set.
Then the rest of your session, do interval training: choose maybe 3 cardio exercises that you can move between easily - say: burpees, SkiErg, assault bike or treadmill.
Then do 45 seconds as fast as you can. In the 15 second rest, move to the next station. Do maybe 2 or 3 rounds - so 6 or 9 minutes , then rest for a minute. Then go again. Keep going for as long as you’ve got time for. Maybe 3 lots of 3 rounds? My PT calls this metcon - metabolic conditioning. I would do about 10 rounds of this sort of thing in a training session after doing strength work.
Second day:
Deadlifts and bench press - sets and reps as above.
Then another metcon session maybe with different stations. Focus on exercises that get your heart rate over the Zone 2 into max heart rate and that are functional - in addition to burpees, SkiErg, treadmill try dumbbell thrusters, wall balls, burpee broad jumps, box jumps. These will all challenge your whole body.