Probably best asked in the webcore forum, as I believe there is an advanced method using the rest API, but it’s complicated and would just be confusing to most people.
I think you’ve already seen the new community FAQ on how routines became a combination of scenes and automations, but I’m going to put that link here for anybody else who findS this thread in the future.
There is a link a few posts down in the FAQ for an example piston on how to get webcore to run one of the new scenes. Since scenes can be widgets, that might help with what you are trying to do.