Is it possible to degrowth from services to modulith?

What I would like to see is a guide and hints how to "degrowth" a small group of "microservices" into modulith properly, especially with nodejs in mind and such, but for other language is ok.
Like, what use and how to migrate various patterns, like message queues, background jobs services, email delivery service, events collector, and so on.
How to organize properly modulith with backend and web UI/pages?
Anyone have such successful experience of project "simplification" and "degrowth"?