The concept of rewarding yourself works for some, it doesn’t for others.
Not necessarily rewarding yourself through snacks that defy the point of the entirety of your workout, but maybe paying for yourself to go to the cinema or something you enjoy when you hit a certain goal, for example monthly?
It’s a hit or miss, some people have the undisciplined attitude of doing that regardless, but I suggest trying it. It also helps to become more appreciative of the littler things and mentally helps you in finding peace in what is usually overseen. It could literally be buying yourself a book, a game, or putting money towards funding a trip/clothes/literally whatever you want.
Sure it’s a money eater, but what isn’t?
Once you get into the routine and thesis of rewarding yourself, you could change the ‘reward’ to something that isn’t costly. Or even if you aren’t able to afford monthly expenses.
Create yourself a spa day, buy some face masks (Poundland sell some good ones ngl) and have the cliche ‘self care’ day.
One thing I actually also suggest is limiting your phone usage, it sounds stupid but you may result to exercise out of boredom. An app I use is called Flora, (they have one called Forest that is the exact same, Idk why) and you can set a timer within the app for x amount of minutes. You can play your playlist beforehand and change songs on your lockscreen, but opening an app/going off the timer will result in it stopping. Basically, you make coins from completing the timer and these can plant real life trees. It definitely takes a while, I’ve been using it for 2 months and have 1300/2500 coins for a tree, but I feel like I am helping myself whilst even slightly contributing to helping the world. It’s real, they have images of their projects and banners and app development with tree planting. You get more coins from unlocking ‘achievements’ from doing x amount of hours in total. Sorry to ramble, but you could also try this app when exercising. This also keeps you more connected with reality and helps you to find a better, mental peace within yourself.