My regular sports team (ultimate frisbee) disbanded after the pandemic, so I found myself without any physical exercise. I thought I probably should go to the gym but realised I wasn't going to do it after work, and neither before breakfast. Also, I am 34 and have never visited a gym before in my life.
Then I found a gym across my office which specialises in High Intensity Interval Training. They are group trainings that only last 25 mins. Including overhead (shower, dressing, etc.) it takes 40 minutes. This means my lunch break is about 1h15 minutes long, but it includes sports!
It has transformed my wellbeing, and I feel suddenly I am acting on issues that I have been procrastinating on for years.
Obviously there are many other things you could/should do in your life. And the other comments here are very valuable. But maybe if you are only going to do 1 thing... Consider this. Or consider it several years down the line when other things have worked out :).