What do "connections" mean

Hello to all,
I have a very basic [strange] question, “what connections mean”
As you can see [here (Imgur: The magic of the Internet)], I have 69 connections to mongoDB. The problem is that this DB is connected to local test project, and I have already 69 connections. I am solo user now, so it is impossible I am using such amount of connections (my opinion). I am using code created by your employee, here, so I think it’s fully adapted to next.js.
The code logic is simple:
A. User requests the info on Vercel, for example getMovies
B. Vercel(or backend) checks if you have open connection, otherwise creates a connection with mongoDB.
C. Vercel gets info from MongoDB and sends to the resource where data was requested.
So, according to logic I understood, I will have only 1 connection open/created, because we have connection as Vercel(backend) - MongoDB, and not Client - MongoDB. With this logic we can’t have > 10 connections. (maybe I misunderstood something)
So, for the questions:

  1. What are connections exactly? Is it “open” connections, “existing” etc?
  2. Can 1 connection properly access different collections?
  3. How multiple users will affect connections? (imagine 100 users requests /getMovies same time). Will it create a connection for each user?
  4. How/when the connections are dropped/closed?(time limits or some logic) and can I force connection drop?

I am asking this info because my project will have an API request for each page, and I will have at least 10 users same time on my web site. So, I’d try to make all styff working exellent with mongodb.