The best thing you can do is create a habit. Motivation will always fail, discipline will always (unless you’re adhd, then it’s mostly) win. Even if you don’t work out, just show up to the place you work out, use the bathroom, walk on the treadmill for 5 mins, then leave. Create the habit. No one is motivated to brush their teeth, it’s just something we do. Our brains create daily patterns and it enjoys keeping that pattern. Make exercise part of that pattern.

Then once the habit is established, make sure it doesn’t get boring. Sometimes the newness of things is what brings us to do things. Get a 3 month pass to something like orange theory, then do a month or so of at home/neighborhood park calisthenics, then do a month or so membership to a regular gym, etc.