Tips for getting in the mood

(Hoping to hear from men and women on this one)
I'm sure many people have similar challenges as well as different challenges. Here's mine:

I've been in a relationship for 1+ years and was in hard mode when we started. At first the challenge was not having sex. Flash forward through COVID, weight gain etc. and it's starting to turn into a once a month thing.

Our relationship is great otherwise (hopefully that's not the problem, I hear from people who fight all the time and then have great sex . . .) but I would like to have sex more, I'm sure that she would and, despite everything, I fear that she doubts my love sometimes, perhaps because of our lack of sexual intimacy.

How can I get in the mood? At least half the time that we do have sex is in the mornings, because my erections are solid and very reliable under those circumstances. At night, I'm usually too tired, too full or both. Maybe I'm just getting old
I also imagine that maybe I'd be more inclined to have sex if I felt sexy. I feel like my sexual desires were much, much higher when I was regularly weight lifting. Perhaps improvement to diet and exercise would make all the difference.

Sadly, I have tried looking at porn and not masturbating to generate arousal, I have tried masturbating and stopping before orgasms to generate arousal, and I have tried masturbating to orgasm in hopes that that would re-activate my system and get me out of this asexual slump that I seem to be in. I hoped that I could turn that sexual energy towards my partner . . . in reality, it turned my sexual energy right back towards PMO.

I'm inclined to believe that my best tips for myself are:

• NO Masturbation
• Focus on health: exercise, weight loss, diet, better sleep, stress
• Drink water before going to bed (more likely to get morning wood)

Any other tips? What has worked for you and your partner?