One of the best kept secret and one that he should have tried is "Kate".
Good old style editor that is a native app, not an electron app. All the features that you might want and more, but simple and efficient.
And the most important for me, super snappy. I can't bear the latency that you get for typing code when using things like vscode. I don't know how people can appreciate that.
Every piece of KDE software I've tried has been buggy to the point that it's now a red flag to me: Spectacle (silently failed to copy/paste), krunner (refused to close), SDDM (refused to login), Dolphin (ffmpegthumbnailer loops lagged out whole system, SMB bugs), System Monitor (wrong information), KWallet (signal fails to open, data loss)
I have had problems with Spectacle related to permissions on Wayland and I think I experienced the failed to copy bug once.
I have not had any other significant problems for some years - not since KDE4. I do not use SMB but everything else works fine and KDE is my daily driver.
Sometimes I have the image copied but it doesn't paste in the browser. However it can be pasted to GIMP. If I paste it there and copy it from GIMP then I can paste it to the browser.
So who's fault is that? Spectacle's or browser's? Maybe wayland's?
Zed is a no go in my book until they learn to respect their users and stop installing third party software* without asking. Completely unacceptable practice, and their reason of "most people will want LSPs to be there without effort" doesn't cut it.
* nodejs specifically, but it wouldn't be ok no matter what the software was. It's my computer, not yours, don't download and run stuff without getting permission.
Zed is fantastic for Rust, C, C++, and similar languages.
I wouldn't bother using it for Web things like HTML, Js, CSS, because it simply isn't better at that than VSCode. Same goes for C# -- as a Microslop technology, you're better off using Microslop tooling.
I know this is just one data point, but I don't notice any latency when typing code in VS Code. It takes a while to start up, and that is annoying especially for quick short editing jobs, but other than that I never notice any sluggishness. Is this something many people experience?
I can tell for you specifically because everything is specific: machine, hardware, setup, projects...
But I always noticed this latency for everyone I ever saw using vscode or computer that I tried.
To be clear, you might easily not notice it if you are used to that and don't know better. And it is consistent with most electron based apps or editors. But there is a very subtile latency between the time you hit the key in the keyboard and the time that it appears on screen. Basically you are typing letters a little bit in advance. With Kate it is like with a basic text edit, characters appears instantly.
The effect is the same when you type anything in web browsers. In form, editor or whatever.
Project size is obviously going to be a factor, but so is machine specs. It's much more noticeable on a spinning disk. One can partially compensate for the project size aspect by opening vscode as far into your project as possible (eg, the api subfolder) rather than at the root. No real solution if you don't have an ssd though.
I'll get into WSL2 situations where it seems like intellisense activity delays the display of characters I type. Feels like the old dynamic dropdown problem.
I used Kate a note taking app synced with syncthing for a while. Using only md files. I had another md based app on Android that worked similarly.
Kate has a decent file browser for hierarchy and it'll stay in place and not return to a weird default path when you close it. And as you said, very fast to open and use.
For one off Notepad like things I like Mousepad especially because it has the Notepad++ feature of being able to save a session without asking you whether it should. Featherpad is also nice for this kind of use.
I'm a big Kate fan as well, used it for years on all my Linux systems. Recently I got a little fed up with vscode lagging on large files, I bit the bullet and installed Kate on my windows 11 work PC as well.
In addition while kate has many plugins, like the one that allows running arbitrary command line utilities with std input the current selection, I would like to point you at something else in case you write / debug SQLs.
Kate has a SQL plugin that allows to send the current selection to the connected SQL server for execution. It displays the output in table form below the editor pane and you can copy paste rows or columns.
That allows to organize your SQLs in markdown files. That was such a productivity booster for me that simply there are no words to describe the difference felt.
Unfortunately there's some thing about their "session management" that makes it unusable for me. I've used it in the past, but apparently differently. (Would have to dig up the specifics)
Kate is great but as others have said. Zed is great too. My combination of text editors is probably zed when I need Gui and Micro editor when I need terminal. Both have great user experience
Kate is the editor i'm using these days on Linux (even though i use Window Maker for my WM and not Plasma) but it does have a few weird aspects. One of them, which annoys me, is that every "tab" is really its own entire editor with its own state - if you do something like search for a word in one file then switch to another tab, you can't use F3 to search for the same word again in that file because that's actually a different editor and it doesn't know that you searched for something in the other tab. This extends to other stuff, as if the main Kate window is just a window manager for the editors it launches in it and it just pretends the UI is shared.
Good old style editor that is a native app, not an electron app. All the features that you might want and more, but simple and efficient.
And the most important for me, super snappy. I can't bear the latency that you get for typing code when using things like vscode. I don't know how people can appreciate that.