Wulaw,
Good on you for sharing your journey.
Down the road when you start choosing different forms of exercise, recognize that just going an working out can get kind of boring, so seek out activities that have some kind of game component to them and also be on the lookout for possible opportunities for joint injury.
Back when I was 45, I was up around 200lbs and made some changes, and pretty quickly got down to 175lbs and looked great. I was kind of reveling in all sorts of rediscovered physical abilities that had been dormant since my early 30's. I don't want to say I overdid it, because I was never really pushing myself all that hard, but some garden variety ailments cropped up. Stuff like Achilles tendinitis, pulled calf muscles etc. So I would rest and rehab and wait it out and focus on other body parts that I could work on safely. Thus began a never ending cycle and rotation of injuries that really made things frustrating.
Fast forward to my early 50's and I was slowly gaining the weight back almost entirely because I could not find the extra motivation to go play and have fun due to some mild depression because of my injuries and fear of re-injury. So over time my normal weight went from 180lbs for a year or so, then 185 then 190, until you see the 200lb man I am today at age 56.
Because you are only in your mid 40's you have time get his right. You really don't need to work out all that hard, so follow your Drs advice on all of that but definitely mix in a lot of flexibility and mobility work, think I wish i had done that would have saved me a lot of trouble. I think rediscovering what your body can do all over again is going to be a huge motivating factor for you. Good luck.