Find joy in simple everyday things because then you'll always have a supply of it. Good fresh coffee or tea in the morning, feeding the birds, watching the sunset or the moon in the trees, stopping to stroke a cat or watch a butterfly. Favourite scent of bath stuff after a hard workout. A good book last thing at night etc.
Make the life you already have more fun instead of thinking it would be fun if/when... I remember when DC were tiny I was mourning my old life one day and suddenly realised I'd never get it back and would be permanently miserable if I didn't change my mindset. If I wanted fun I had to have fun with DC. From that lightbulb moment on, we went out every weekend to steam fairs and miniature railways, we built dams in rivers and made mudslides, we sledged to school on snowy days, we built dens and bonfires, went to circuses and immersive art shows etc. We had fun all the time. People used to say you do so much with your family. But DC didn't do nearly as many clubs as other DC so we didn't spend hours ferrying them to and from an exhausting program of after school things. Now they are adults we still all have fun together going to theatres and gigs and cocktail bars.
Decide what your absolute top priority that brings you most joy is and pursue it. For me that was DC so I chose to go part time at work and WFH throughout their childhood. Meant I was not often stressed by work.
I see a lot of people in the wealthy area where I live work all hours then spend the extra money on gardeners and cleaners and nannies to love their life for them. I'd genuinely prefer to work fewer hours, mow my own lawn, polish my own floors and bath my own kids. I don't understand the constant need for stuff. I'd always rather have time.