I am a deep enjoyer of Typst. I love it and I use it absolutely everywhere that I can.
CeTZ is a really good package, but I still reach for a tool like Omnigraffle if I need to make a really complicated diagram.
I do like Typst, but Typst isn't really ideal for diagrams... you could use it that way but I don't think it's ideal. Mermaid or PlantUML are better/cleaner options.
Agreed. My resume and slides are all templated with Typst, but I can't be bothered trying UML languages to make diagrams that'll probably be referenced once or twice a year, if ever.