@nprofile1q... I was the same most of my life as well, and if I went back in time to talk to my older self I am sure they would be surprised to see me now as a gym rat.
What helped me to start my fitness journey was to turn my workouts into a game of sorts. For example I would build a music playlist with a specific BPM of 145-150 and run the treadmill to the rhythm of the song that was playing, timing it so that my foot lands to the beat of the music.