A solution to work with room reservations?

Question

CMS

Kind. Need advice on how to put together the following scheme of work.
There is a booking form. Accordingly, there is a phone number, full name, date, time, room, etc.
What you need: when an application is received, it falls into the admin panel, where it is approved / rejected, and the user receives a message that the application is in response.
Ideally, whatsapp and telegrams would be fastened for notifications (that is, the number). A completely ideal option is also an appropriate auto-add to Google calendar (for each room).
The question is how can this be implemented with the least labor and financial costs?
What options do I see:

• Based on wordpress via supportcandy plugin or via CF7
  
• Install TicketOS and work through it
  
• How to integrate here bitrix24.
  

What other options are there (or is there something ready-made?). Everything is needed in the browser and with understanding by people who need it no more complicated than VKshechki.