Firebase for complex query. A no go?

I've moved from parse-server to firebase for my new project, but reached a point in the project where I beginning to think it was a bad idea.

Basically, I'm making an app where people can post information about concerts going on in their town.

My first challenge was to filter the events, so a user only get events in his/her own town. I did this by structure the data after cities:

{
    concerts: {
        "New york": {
            ...,
            ...
        }, 
        "Chicago": {
            ...,
            ...
        }
    }
}

Then I figure I need another filter for the type of concert, e.g rock, pop, etc. So I though I did another restructure. However, there probably need to be 5-10 more filters, and it will become very hard to structure the database in a good way.

I though about multiple query, but this wasn't allowed:

firebase.database().ref("concerts")
.orderByChild("type").equalTo("rock")
.orderByChild("length").equalTo("2")
.orderByChild("artist").equalTo("beatles")

I thought about fetching everything from the server, and then filter the result in the client. I see however two problems with this:

There might be a ton of unnecessarily data being downloaded.
Some concerts will be locked only to certain users (e.g users who have gone to at least 10 other concerts), and there might be a security aspect of pulling home these concerts to user not being allowed to see them.

I thought about combining filters to create query keys, like this this, but with over 10 filters, it will become to complex.

Is there a solution to this or should I forget about firebase for this use case?

Thanks in advance

Incredibly complex queries can be crafted in Firebase. The data needs to be stored in a structure that lends itself to being queried and most importantly, don't be afraid of duplicate data.

For example, lets assume we have an app that enables a user to select a concert for a particular year and month, a specific city, and in a particular genre.

There are 3 parameters

year_month city genre

The UI first queries the user to select a City

Austin

then the UI asks to select a year and month

then a genre

Rock

Your Firebase structure looks like this

concerts
  concert_00
   city: Memphis
   year_month: 201706
   genre: Country
   city_date_genre: Memphis_201606_Country
  concert_01
   city: Austin
   year_month: 201704
   genre: Rock
   city_date_genre: Austin_201704_Rock
  concert_02
   city: Seattle
   year_month: 201705
   genre: Disco
   city_date_genre: Seattle_201705_Disco

Your UI has already polled the user for the query info and with that, build a query string

Austin_201704_Rock

and then query the 'city_date_genre' node for that string and you have your data.

What if the user wanted to know all of the concerts in Austin for April 2017

queryStartingAt("Austin_201704").queryEndingAt("Austin_201704")

You could easily expand on this by adding another query node and changing the order of the data

concerts
  concert_00
   city: Memphis
   year_month: 201706
   genre: Country
   city_date_genre: Memphis_201606_Country
   city_genre_date: Memphis_Country_201606

And depending on which order the user selects their data, you could query the associated node.

Adding additional nodes is a tiny amount of data and allows for very open ended queries for the data you need.