I can promise you that you are definitely not alone--kids are a TON of work, more than anyone will ever tell you.
I was in the same boat as you, great jobs, nothing to really complain about and turning 40 with kids 3 & 5 when COVID first struck in 2020. In addition to those ages being a grind already we had them at home 24/7 so it was a double whammy and shock to our already stressed out world.
It does get easier, although with it comes new challenges (shuffling nonstop to kids activities, social/friends things, etc). Having said that, your overall quality of life will increase--even little things like not traveling with car seats, having kids go to the bathroom themselves, going to a restaurant without taking a bag, kids coming down and making their own bowls of cereal, etc make a world of difference. It's a grind in those early years through 5 but keep grinding is my advice. You only get one chance to be a father and the days are long and the months are short. I'm not sure where the time has gone to be honest. We're in that nice age now before the real teenage problems set in with their own set of real life issues.
Aslo, my advice would be to wake up earlier and get some time for yourself--go for a run when everyone else is sleeping for example. Good luck.