Nope, I could not disagree more with this, and I never understand when people say 0-1 is harder on threads like this. You are more than doubling your workload with 2 as not only have you got to manage 2 children together, you also have to deal with the requirements and responsibilities to parent them both separately as individuals. It's an awful lot to juggle. I have a 28 month gap and the first was not in nursery when number 2 was born, so I had 2 children to care for 24/7 - it was fucking carnage. I find often when people say going from 1-2 was easier they mean that child number one is in nursery full time (or even part time), so the amount of time parenting 2 together is actually much reduced, so individual circumstances matter when people comment, as does the nature of both children, and the sleep situation as a PP said.
That being said, it's all kind of irrelevant as having 2 children has made me the happiest I have ever been (whilst also nearly killing me). My youngest is coming up to a year now, and without doubt it's been the hardest 12 months of my life, but I wouldn't change anything - it's a wonderful age gap and seeing the pair of them build their own relationship, independent of me as their mum, is just magical. They're a proper little team and being privileged enough to watch that grow is incredibly special.
OP, you'll get lots of opinions here, and some will have found the change harder than others, but none of that really matters. What matters is what your gut/heart says. It's ok to be one and done, just as it's ok to be terrified of the prospect of a second but do it anyway because the urge to have another is stronger. I knew if I didn't try for a second I would regret it, but I went into it with my eyes open and the reality is proving as hard but as delightful as I imagined/hoped it would