Hey,
If it’s of use to anyone, I’ve just written a small PHP script which you can point your alerts at using the Send to Web Site functionality, which will take the data (use the “Post event details in XML” format) and post it into a Microsoft Teams channel.
It’s pretty basic, and I already have ideas to improve it, but it does what I need for now.
It’s available here: simplehelp-alerting · GitLab
Nick.