A few ideas I hope might help (tone: I’m offering these ideas sincerely and without any judgment, because I enjoy being active and the health benefits I get from it, and I want other people to be able to feel that way too if they want to):
1. Make sure the way you’re choosing to be active is something you enjoy, because it should be! Both so that you get the most health benefits from it and to help you stay motivated. If you’re not having enough fun at the gym to keep you motivated, maybe you need to explore new, different ways to be active that you might enjoy more? Is a different activity in a different setting possible, or different equipment/activity at home or at the gym if that’s the most convenient/accessible for you? Or maybe you need something extra to enjoy at the same time, like an audiobook/podcast/music/tv show to occupy your mind while you’re exercising?
2. Make it part of your routine so you don’t have to make so much effort to choose it. A lot of days I exercise in the afternoons just because it’s become my default: it’s part of what I always do in between getting home from work at 4ish and having dinner at 6-7ish. (Unless I don’t feel well, or there’s something else I need/want to do more.)
3. Do you need to work on your relationship with exercise? Make sure you have a positive, healthy outlook, attainable goals, and that you practice listening to your body. Maybe find some new body-positive, movement-positive people to follow on socials for ideas and inspiration? Start small, and reward yourself for your efforts! I like to give myself a check mark on my exercise room wall calendar and log my activities in a habit tracker app so I can look back and see how much I accomplished each week/month/year, because each day adds up!
Good luck! :)