I think diagrams are usually quite helpful in accompanying an Architecture.md doc, especially if it gets complex.
I work on a diagram maker that syncs with a Github repo. So whenever you make changes to this architecture diagram, it'll push changes to the repo, with screenshots directly in the README (turning the repo into a diagram presentation).
This also allows people to colocate the diagrams alongside the code or docs by including the synced repo as a submodule.
An alternative is to use an embedded diagramming syntax like dot or mermaid such that the diagrams are described as version controlled text and optionally rendered inline by e.g. VSCode. Cleaner than a litter of side car images in which it may be unclear what changed.
Text based diagrams definitively have their advantages over wysiwyg editors. However, sometimes the layout of a diagram also tells a story and I find it hard to express that with available text based diagram solutions.
That's what I use draw.io aka diagrams.net for.
I made an extension that helps to create markdown-embeddable/versionable draw.io diagrams in vscode:
https://github.com/hediet/vscode-drawio
(there is also an IntelliJ extension)
I have to admit that I sometimes struggle with pixel perfect layouts though and rearranging nodes is time intensive.
However, most text based systems don't have a nice github integration and rely on manual export, which you can avoid when you diagram is not a plain text file but a rich diagram editor.
I work on a diagram maker that syncs with a Github repo. So whenever you make changes to this architecture diagram, it'll push changes to the repo, with screenshots directly in the README (turning the repo into a diagram presentation).
This also allows people to colocate the diagrams alongside the code or docs by including the synced repo as a submodule.
https://github.com/terrastruct-bot/Demo