Amp is the wrong product, you will need a Sonos Port.

Why ask this question twice under different titles?

The Port is the correct product, however…  You can use a device that steps down the amplified signal to a line level signal, such as this:  https://www.amazon.com/Russound-ADP-1-2-Speaker-level-Line-level-Adapter/dp/B01KYHD5SC/ref=sr_1_4?crid=3M94Q19NQULUR&dib=eyJ2IjoiMSJ9.vr_4rW80V1lgCUrg5GhiiMrdJGZQGf22hU4dJRofqEWRGwwA2ZqX6cMj8yWJ6ZiHc7n9sPiYsjtQR8rLjyHLdbBYGZyFcAESjMtt84RpwS26pVWIy-sb2zRZdLnHY6Ev7OpuktNPaMed6_UmwfVfTXroqQaQ7v-sWcN_TG0gmJlQ4TgVquRy03aYUsO3srWHa5mMHnOHFFTvTzowA5Y59omAM9JQkxvGBE-xNmmeKpk.cbhsYaizmqoKkruAgHeXncevYaQfjx3Gt9eUZx6-ivs&dib_tag=se&keywords=speaker+to+line+level+converter&qid=1721130908&sprefix=speaker+to+line+level+converter%2Caps%2C109&sr=8-4

The problem with this device is the amount of power it is designed to handle, and I can’t find a spec on it.  Your Amp’s output is rated at 100 w/ch, which is a lot for one of these converters.  I have to point out the correct way to do this, given the large investment in the Beolab 18’s, is to replace the Amp with a Port, and connect the Port to the Speakers with RCA cables.  Honestly it’s a little crazy to cut corners when you’ve invested what it takes to buy the 18’s.

There are various ways to deal with this, starting with a basic product such as a level converter. 

You guys are so resourceful! Thanks! Love my Amp + Sub (and beam in bedroom). Probably I should go for other passive speakers instead of the Beolab 18.