There's nothing I can say to convince you Ubuntu is sucky if you don't personally experience problems with it/have the occasional "I wish I could do this, but I guess it's not possible" thoughts—spoiler: it's usually possible, just not with that distro; this is true for all distros though, there will always be things they cannot do that others can.

That being said, my biggest gripe with Ubuntu, besides canonical's geologic-paced attempts to make it profit-driven (which was what I was thinking of when I mentioned user-friendliness), is Snaps. I understand the motivation behind them, but the implementation was just sucky for many nitpicky reasons that I don't really care to enumerate rn.

I also just don't see much value in downstream for my needs. I can basically turn Debian into a Ubuntu clone if I want to, and my packages will still largely be supported by upstream maintainers. For bespoke distros it makes sense, but those are usually ill-maintained or hobby projects that update at glacial speeds.

I'm not saying that Debian >>>>> Ubuntu. It's better just enough that I'd recommend Debian before I would recommend Ubuntu.