Every stage has its ups and downs, personally I loved the baby stage each time and would say (looking back with my so-far -10-years experience of parenting) that birth to nine months was when I felt happiest, most secure and most confident. I just instinctively felt it was doing it 'right'.
From about 9 months old onwards it got a lot harder for me-babies got mobile, clingy, fussy, etc. I found the toddler stage incredibly hard and frustrating (am right in the thick of that now, with 23mo DS3). Potty training is a literal hell. So are the tantrums, the increased fussiness, the physical strength to fight you when they don't want to go in the car/buggy/supermarket trolley etc etc etc. You worry about their development, their speech, their motor skills. Are you doing enough with them? Too much? Too little? Etc etc.
I have genuinely enjoyed from about 3-7 (not as much pure simplistic happiness as the baby days, but the 'middle childhood' stage is a lovely one) but the challenges ramp up. Are they developing ok at school? Making friends? Is their reading progress as expected or a cause for concern? Any sen emerging? Etc etc. Same worries about are you doing do much/ too little and so on.
Upper primary brings more independence but again more challenges. More complex social situations, more complex homework / exams, are you doing enough, too much, too little. Are they going to cope at secondary school? Are they safe online? Are you allowing enough independence? Too much? Too little? Etc etc.
I can't comment on anything beyond 10, as I'm not there yet, but I'm dreading the teen years as possibly the worst yet. More pressure, more expectations, are they achieving, are they ok socially, are they safe. How much freedom, how many boundaries, etc etc. Lying in bed waiting for them to come home, hoping they're ok. And so on, and so on.
So no, I don't think it gets easier. Yes, babies are relentless, but each stage is hard in different ways. Joyous too in different ways, of course, and to each parent some stages are more enjoyable than others. But I don't think you should hang out for your life getting easier as your DC gets older. It will be fun and amazing in so many ways but an utter bloody stress fest in others.