I use some site designs I apply through HTTP REST call.
Initially, I used the ApplySiteDesign function, which is synchronous.
However, it started to fails with some site designs. No error returned but nothing applied. I guess this is due to the number of actions, which is limited to 30 (red that somewhere, not in the doc :()
I then fallback to the alternative AddSiteDesignTaskToCurrentWeb function.
This method works for larger site design but is asynchronous.
Is there a proper way to wait for the end of the application ? The data returned by the function isn't usefull (or at least I didn't find how to use it).
If it matters, I perform this calls using PowerAutomate workflow.
As a workaround, I ended up by adding in my site designs, at the very end, the creation of a dummy column, and in my process, I loop trying to get the column (still through rest) until it's success. Working, but quite ugly.