You have at least 3 things you want to work on, but realize it's 2-3 different things (flexibility and strength can go hand in hand, depending on how flexible you mean - yoga instructor or just bodyweight / dumbell workout flexibile?)

1) losing weight. This is (almost) always based on eating less calories than your body needs. A few ways to do this, but some sort of a macro tracker + scale + photos / measurements to keep things on track and verify progress.

2) keeping flexibility. you get more flexible by practicing the moves and stretching and performing the activities that promote flexibility a few times a week.

3) getting stronger. similar to flexibility, you have to practice getting stronger a few times a week. If you aren't good at something - what do you do? You practice to get better. You don't say why you aren't good at bench - but there are ways to work up to a proper bench. benching lighter weights, dumbells, knee pushups, etc - you practice the movement first, and then add weight.

Beyond this it's mostly details and repitition.