I'm a new overweight, I need help

In 2020, I was diagnosed with OCD and depression. So I started gaining weight like never before, I was 183 cm ~ 6 ft, 65 kg ~ 143 lbs, now I'm 120kg ~ 246 lbs. My weight is getting out of hand.

so, I started working out, then I noticed that when I do cardio my heart start bumming out like crazy, I'm working out from home duo to some personal issues, and using an app called BodBot when I do some exercises it start hurting my knees like "Door frame rows" exercise.

It's nearly impossible to see a doctor. So I want to ask my friends here, what should I do?