I just learned about UML earlier today when I wanted to bring in a mermaid flowchart into lucidchart. If you bring in mermaid using lucidchart, it makes it a raster image. But if you use UML markup, you can ungroup it and modify. I couldn’t get a good way to convert from mermaid to UML markup that lucidchart could handle. Ended up a dead end for me.

On a similar note I've had various annoyances with wanting to round trip diagrams from Mermaid or PlantUML into Miro and vice versa. There doesn't seem to be much out there to facilitate this, which is strange, because it feels like a very enterprisey thing to want to do.

There's probably a SaaS product in it for someone sufficiently interested in the topic... probably not at unicorn scale, but enough for a side income perhaps?