You can have the following combinations

1 The Beam as your front channels with the One SLs for the rears, and your Amp and passive speakers in a different Sonos ‘room’, i.e. not part of the surround setup

2 The Beam for the front channels, the Amp and passive speakers as surrounds, and the One SLs not as part of your surround setup

3 The Amp + passive speakers at the front, One SLs as surrounds and the Beam redundant.

You cannot use all your speakers in a surround setup.

Also, you need the speaker(s) that don’t fit into your surround system to have a different room name from the surround setup - having the same name only creates confusion.

You can group other speakers with your surround setup, but they won’t sync perfectly for TV sound (they will do so for music).

Thank you John, but overall that is sad news for me I’ve read somewhere that I can use this combined, I guess here on the sonos community, by making the sound bar a “phantom center speaker”. If I had known that I can not use my AMP as front speakers within my audio setup I would have gotten the Arc instead of the Beam.

You must have remembered it wrong. The “phantom center” is what the Amp creates to make it seem like you have a center speaker when in fact the Amp only drives two speakers (hence "phantom’- it is not a real speaker).

You can use the Amp as front speakers - see my option 3.  As @106rallye says, it still covers the three front channels, creating a ‘phantom’ centre.