I don't know if this will be helpful at all, but I'll tell you my experience. So I'm also 30 and I work about 40 hours a week. I workout about 5 times a week after work. I didn't start working out until I was 24 and at first I hated it. I dreaded going to the gym but I forced myself to do it anyways most days. After maybe 2 weeks weeks I started not hating it anymore. I still didn't like it, but I didn't hate it. Then after a month or so I actually started enjoying it. Once I started being able to see some results when I was looking back at my first progress pictures I really got into it. At this point I actually love going. It's the thing that actually keeps me going on a long shitty day at work because it's like a treat for me at the end of the day.

My friends or coworkers will often say stuff like your question like "Man how are you so disciplined to go every day?" or "man I wish I could be motivated like you". I'm not saying that to sound like I'm bragging or anything. To me it's just funny because I am not either one of those things. I just love going now so it's more of a hobby that I enjoy rather than some thing I'm forcing myself to do just because it's healthy. I actually get bummed out now on my rest days when I know I'm not going to the gym.

I don't know if that helps at all, but that's just my experience. At first I just had to brute force myself into going every day, but after a little while I actually started looking forward to it and now I love going.