Using iMac 2017 as a display for MacBook pro 2019

Nope’ because a 2017 iMac does not support Target Display Mode. Plus even if you had an iMac that supported TDM, the 2019 MacBook Pro could only be running Catalina.

carefully read > https://support.apple.com/en-us/HT204592

The answer to that, is at > https://support.apple.com/en-us/HT202351

You are correct, it won't work.

Jack

Danisdylan wrote:

But, I could use the 2017 iMac as my main computer and connect it to two monitors?

Sure

You’re welcome.