I see your problem. If you want formatted text
No, what I want is support for images, file attachments, speed of entry and search on mobile devices, crossplatform use - at the very least, iOS, MacOS and Windows, OCR (not a 100% requirement but very much wanted) and data portability.
If you read my post that you quoted, that's what I am talking about. Images and attachments and speed of use on mobile.
As far as formatting, I really care very little about it. If I could get a fast cross platform information manager that supported inserted images and file attachments and could export in some common format preserving file names and relationships, but had zero formatting options, I'd be perfectly fine with that. It's icing on the cake.
there is no solution really except the docx which you are hoping that MS will continue to make it available for import to other apps (I think they can withdraw that capability).
MS was forced into opening up their formats - the old .doc was a closed format, the current .docx is an open xml format and is basically a zip file with resources. The standard is open, so it's not up to MS to allow importers.
For formatted notes with attachments Evernote excels and for a heavy user the $10/month is worth it but you will be locked into their format.
And it doesn't support Spotlight. Unless tags are absolutely required, Onenote makes more sense - it's also great for formatted notes with attachments, and is a whole lot cheaper (or free if you can stay within 5 gb). Also a proprietary format.
I am not sure how Obsidian fares in comparison.
It's a closed source app using markdown. I already wrote pretty extensively just how broken the markdown format really is due to fragmentation and variable standards. It being open creates an illusion of portability, but because every other implementation does something different, the data is not really portable unless you're using very basic features, basically just a glorified text document. Once you introduce things like relative links and images and cross platform use, it breaks pretty spectacularly. I tried four different MD apps and all four had a different way of making links and images work. I couldn't read a link made in one app on another without editing it. I would not rely on being able to access all my data, with image and file links preserved, ten years from now without having to re-edit all files.
I would choose .odt since its open source so I am hoping there will always be someone who will pick it up in the future and build an app around it.
Except Docx is also an open format, and it's a whole lot more used. When I tried to find iOS apps that support ODT a few years back, there was just a few. Collabora Office was probably the best one, and it was still fairly clunky. OTOH, there's a ton of apps that support Word format. It's basic supply and demand. Just because something is FOSS, doesn't mean it's more future proof or more available - it's an illusion of freedom.
Regardless - there's two reasons I don't use Word (or Open Office) files. First, mobile. When I am taking a note on the phone, or am looking for info, I want it to be as fast as possible. On the desktop, it's much easier to do things fast even if the process itself is not optimized. On a phone, the app must be set up for quick on-the-fly data entry or retrieval. But because the developers think of Word / OO docs as "documents" and not "notes" nobody is trying to optimize their word processors for quick notetaking. Things like autoname, autosave, automatic zoom to maximize readability. It's doable, but nobody is doing this.
Second, file attachments. There's no such thing. You can only use links. And links are iffy, especially in a cross platform, mobile and desktop environment.
Have you tried DevonThink? one of their export options is MS Word.
Devonthink is expensive and does nothing for cross platform users.
Realistically, there's no truly portable, future proof setup if you need file attachments. FOSS doesn't ensure anything because you're still locked into the specific way the specific app does things, and just because "anyone" could restart development if the original team quits, doesn't mean that anyone would. Certainly not in any defined timeframe. At the end of the day, it's a collection of proprietary solutions, even if the code behind some of them is open.