A lot of people absolutely adore telling other people that things will only get worse.
No more delicious phrase than "just you wait" unless it's "if you think this is hard, you ain't seen nothing yet"
I don't know why but parenting brings this out in people.
If your baby doesn't sleep someone will try to tell you that potty training or toddler tantrums are harder. If your toddler is having a tantrum mid potty training someone will tell you teens are so much harder and they miss how easy potty training and toddler tantrums were.
People are gigantic arses who love to play the battle worn expert while terrifying anyone behind them on the time line.
I have two teens and an 8 year old. Mine were all easier once mobile, even the climber... DC1 walked at 9 months and a walking tot is way easier because they can play in the garden. Dc3 crawled at 7 months and learnt to climb almost immediately which was harder - he literally climbed door frames right to the top as well as curtains and his favourite was book shelves - I had to remove all the shelves from inside the living room book shelves for several months.
However it was still easier as they're finally happy not being carried once they're mobile and get less frustrated.
All mine were easier once walking especially. Just toddler proof a room so you can go to the toilet, and think creatively (worked for 2 of mine - a determined climber you'll have to take with you...)

enjoy. They get more fun from 5 or 6 months and it only gets better.
Nothings been as hard for me as sleep deprivation in the early years (I did have one exceptionally bad sleeper and one who was a bad sleeper until mobile die to reflux, and dc2 was my "control" baby who was a pretty average to good sleeper) .