i really, really strongly recommend trying exercise too. diet is very important, and i think following the advice in other's comments is still a great idea! but even for people who are physically disabled in ways that limit their ability to exercise, it's vitally important to health (and not just to lose weight, to keep our bodies functioning properly).
exercising doesnt have to be 40 push ups or running a mile or going to the gym or anything grand like that. it can start really small. i find that home yoga is very good for keeping the body mobile and strong, and it's a pretty relaxing form of exercise when done right. i like japanese radio exercises for the same reason, but that may not be your style. you could learn chair exercises that are meant to be done at a table or desk, and even doing a few leg lifts from bed can be excercise. you can find tutorials for these online. things like this may not make pounds of difference, but they can still help to raise your metabolism - and eventually you may find yourself wanting to increase the duration or intensity of your exercise in ways that will more drastically impact your weight.
it gets a lot easier to do consistently with practice. starting out, it's really hard to get motivated, but after starting slow with a simple and easy routine, it will quickly just become a normal part of your day. i recommend the app finch here - it's a great general health/self-care app with a cute pet you raise by completing self-care tasks. they have these kinds of simple exercises as possible tasks and they offer a gif and a timer to help you do them.
i lost around 50 lb for the first time in my life by starting small with my exercise and building it up, along with changes to my diet. i had tried calorie counting, beach body diets, elimination, changing my meal times, and none of those alone made much difference because i tried to use them without exercise. (i also had to be a lot more aggressive with the diets because of it, so they were usually not very sustainable). if you really want to lose weight, especially if you want to see quick progress, you will need to get over that lack of motivation.