I want to motivate myself to do this so bad but I have trouble because it takes so long to get into shape

I'm not overweight but I'm still a bit on the chubby side and I have a lot of stretch marks on my body from back when I was overweight as a child which make me feel worthless and ugly lol. I want to do something about it but I don't know how to motivate myself because I find most of the physical exercises that I've done so freaking boring.

How do you motivate yourself to put the work in for this among all of your other issues? Because I always end up either putting in 1-2 weeks worth of exercise and giving up when I don't see any noticeable changes in my body or outright put it off all together.