Having looked at it a bit more, even if it doesn’t end up replacing Standard Notes for me, it still looks promising, particularly given the ease of self hosting it. Self hosted it looks like it could be useful for shared notes, too, even though that doesn’t seem to be its intended use case.
A big part of the appeal for me is that Standard Notes already had a bunch of editors and that it was easy to create my own - they provide a starter app and you can just use React and/or any web libraries of your choice. I’ve looked through the Trilium docs and while they’re not as good, they’re probably good enough.
Another big difference is that Standard Notes also sandboxes its editors, such that they only have access to the current note. It looks like Trilium’s executable JS code notes lack a similar feature. Then again, that also has a positive side effect of meaning plugin devs have a lot more power and flexibility in terms of what they build.