New iMac with m3 chip using multiple monitors

I am doing just that! Those 2023 iMacs are trash, which is a shame as I have used them for 20 years now. Between a limit of 24” display and monitor limit of one, yeah, totally a step backwards. Kinda ugly too.

There is no way to add more first-class hardware video outputs to a 24" M3 iMac. The limit of one external monitor is clearly spelled out in the Technical Specifications that were available before purchase.

There are workarounds. None is as good as first-class hardware video output. You may encounter issues such as lags, artifacts, inability to play DRMed video content, and the possibility that the software needed to operate your workaround product might break when a new version of macOS comes out, leaving you dependent on the vendor (or their technology supplier) for a fix. These types of products are best if you have relatively static content – you might not be too happy if you used them to try to play high-end video games.

For instance:

Other World Computing – USB-C Dual HDMI 4K Display Adapter with DisplayLink

SonnetTech – DisplayLink Dual HDMI Adapter for M Series Macs

SonnetTech - DisplayLink Dual DisplayPort Adapter for M Series Macs

These three all rely on DIsplayLink technology from Synaptics. So you would probably download the software that you needed to make them work from the Synaptics site:

Synaptics – DisplayLink Graphics

If you purchased directly from Apple within the past 2 weeks then return the iMac and purchase a Mac Studio, the MS has the ability to support up to 5 external displays.

if you did not buy the iMac directly from Apple then contact the reseller about their return policy.

The 2017 27" iMac supported two cabled external displays.

see "Video Support" at > iMac (Retina 5K, 27-inch, 2017) - Technical Specifications

The 2023 24" iMac only supports one cabled external display.

see "Display Support" at > iMac - Technical Specifications - Apple