Surprisingly high-performance plugin

I am creating a matching site for tennis events.
The site is a member site, where the organizer posts an event from the frontend and the member applies (registers) from the frontend. The notification of the application will be sent to the organizer by e-mail, and when the organizer confirms the applicant for participation, the notification will be sent to the attendee for participation.
The site need an event list page, a dashboard for organizers, and a participation application list page.
Since it is a multifunctional site, it was estimated to be about 1 million yen when custom designed.

I’m an amateur and I don’t have that much money, so I thought I’d make a site with just wordpress and plugins. Initially, I installed Ultimate Member, WP User Frontend pro, Search & Filter pro, Front End PM, The Events Carendar and so on. However, I had a hard time integrating each plugin. At one point I learned about the existence of WP Event Manager.
WP Event Manager (+ Ragistrations) and Ultimate Member are all I need for my site.

My request is to have the organizer and Attendee contact only the front end, so it would be great to have a private message with email notifications add-on.