I think it’s more subtle than that. I am a power user — I was compiling my Linux kernel in the 90s, I wrote my own SSH tunnel manager 20 years ago, I always fiddle with settings, etc. etc.
However, I am constantly frustrated with a lot of OSS software because it expects you to think like the developer of the tool, instead of having empathy for the user. What feels obvious to the developer of the tool (I am making up a hopefully-representative hypothetical here, but finding the change of font under “Theme” because it’s how “it looks” but finding the font size under “View” because, well, you view it) feels frustrating and nonsensical to a normal human who relates both the font and its size the same way in their mind. Again, generally — I’m making generalizations here and not calling out any specific software, but trying to illustrate the feeling that I get.
When I switched to the Mac in 2002, it is because these sorts of things made sense. Yes, there were and are frustrations because of this sort of opinionated design mentality, but I judged the benefits to outweigh the positives. Unfortunately, Apple squandered this culture and skill and nowadays I often find the platform as frustrating as OSS ones, to the point where I have switched back to 50/50 time split between platforms.
OSS software aligns mentally with "tool". It only exists because someone had a problem to solve, and they wanted a tool to solve it. Generally, people should expect to have to learn how to use tools. Then they solve their problem and move on. It takes effort, and the result is mastery which gives you new capabilities.
Consumer software (and especially anything ad supported or social media adjacent, and sadly in many respects, lots of modern SaaS companies) want to be as glitzy and smooth as possible, but they don't actually want you to solve your problem. Instead they'd really prefer that you simply spend as much time looking at their software as possible. So the experience can be quite pleasant, it feels nice, things feel obvious, you get the dopamine hits quick and fast. But after a while you realize you aren't actually all that productive (or even productive at all) when engaging with them. Because the goal of this software isn't to help you solve your problem. The goal is to keep your attention and extract your money. If it happens to solve your problem... sometimes that's fine, sometimes that's actually counter to the primary mission of extracting your time and money.
Afaik koreader itself does not support stylus while the default reader in kobo does (somebody made a plugin lately but not sure how stable it is). Not to say that koreader is not amazing, but it does not mean that FOSS always has strictly more features. If koreader had strictly more features and I wanted some of them I would choose that. But I also right now want to use the ereader to read books and take notes, not tweak plugins and configurations. I have been in this "power user" loop where I spend more time with configuring rather than doing the thing, and I am a bit more selective with when this makes sense to me.
This requires however to remember the name of the command (or parts of it). I often remember that but not where to find it or the shortcut.
It also requires that you chose the spacebar search option, which is the only correct option if you ask me. (Not a pro. Just messing around with blender sometimes.)