0-3 is hard I think - esp physically. Cute but really hard because it's all new too.
You start getting to really enjoy things at 5, post potty training and when you get to tail end of preK - more opportunities to meet other parents, etc. More personality comes out at ages 5-6. Travelling is easier to some extent.
The really awesome years for us were the elementary school years of K-5. Really busy though with more activities but they are little humans and you can take them and do stuff, watch movies, lots of family time. Holiday school/events are a great time. It's a great few years.
I'm now at the MS years of 10-14. UGH. The drama of the boys and girls! The electronics are out of control. The expenses are back for activities, sleepaway summer camps, if your kid needs tutoring/learning disability support/therapy - you can't escape it for this age even if you skipped it younger. The homework help, carpooling, now they are really people!

LOL
Puberty and hormones are a real thing. You can get lucky for sure with your kids but this is the age where it's been hardest for us - all the earlier stuff was way easier and the school years of elementary were super easy. The good stuff is that you can actually have a date night out, you can watch shows and travel more with the kids. They can make breakfast/lunch on their own, it is definitely easier physically. Not so much worrying about playdates and birthday parties. But you worry more about school, grades, mental health of course.