The absolute best might still be Styluslabs Write, which has very nice editing capabilities and I prefer its "pencil case" tool model (you have multiple tools with colour, shape, hardness, etc.). But it's closed source, doesn't run natively under Wayland, and I like Rnote's smoothing more.
I agree that Rnote's smoothing is better, but its tool selection UX is terrible. There are three different bars (top, bottom, and side), and you often need to move your mouse/hand to all of them across the screen in order to select the right tool. In Xournal++ I can put everything on the top bar.
Xournal++ has it's own problems. Pasting an image always makes it so big, that resizing to the correct size is difficult. It also doesn't have a laser pointer, which is why I can't use it for teaching. Creating a new document with the correct template is also painful.
Honestly, in another life, I would write a decent note-taking app.
Besides selecting/manipulating with rectangle/lasso/intersection selections, handwritten text that is roughly level with the page rules can be deleted/moved by using the stylus as a "cursor." It understands punctuation and descenders and works surprisingly well. Text that is pushed too far to the right even "reflows" to the next line. The site [1] has a good explanation of how this works.
Rnote looks nice too though. I wonder if it'll be able to match the UX of Write.