Dad of two boys here.
Sometimes I think I'd give my left nut to have no responsibilities again. Just be able to blast through a 50+ hour game in a week or go on an impromptu beach trip with my wife.
Having kids is HARD. It's extremely difficult! I barely cleared having two under two (oldest was 25 months when his little brother was born). We are almost at 3 and 1 now and it's still hard.
BUT.
Kids grow up. My oldest talks in full sentences now. He's a breeze in comparison to his baby years. And my youngest is the most relaxed, chill little guy ever (polar opposite of his older brother). Watching your kids grow and change is amazing. Watching the growth and change in yourself is also amazing. Watching the growth and change in your spouse/partner is amazing! I love seeing my wife with our kids. She's an incredible mother. I had been with her for nearly a decade before we had kids, and I always knew she would be a great mom. Now I get to see it every day, and she gets to see me be a dad.
So yeah, even though shit is really, really hard right now, it's not going to be this hard forever. As I said above, kids grow up. It seems like people think having kids=being up all night and changing diapers forever. In reality kids are usually sleeping through the night between 6 months and 1 year, and out of diapers by 3. Then you've got about 8-9 years of true childhood before they are tweens/teens and want nothing to do with you. Then you survive the teen years, and next thing you know you're visiting them at college for the weekend. Then you're giving them advice about their first grown-up jobs and health insurance and retirement accounts. Then, if you're lucky, they're spending a lot of time with you and even bringing their own children around.
Assuming you aren't ancient when you have kids, you should think of having kids not as having literal "KIDS" but having children of your own, and those children, God willing you live a normal lifespan, will be adults for decades of your life. You will be a parent to a child for a very short period of time, but to an adult for much longer. I know my parents were often wistful about my and my brother's childhood, but the relationship they had/have with us as adults is the best part of parenthood. I hope that's the case for me, my wife, and our boys.