HDMI Port On Macbook Pro

You failed to post the relevant info - the tech specs/model/year of your devce. I just guessed and pulled up the specs for a 2020 and, if this is yours, there is no HDMI port, but you can use adapters:

MacBook Pro (13-inch, 2020, Four Thunderbolt 3 ports) - Technical Specifications

well, all I know is that many many M1 users of every model Macs that have an HDMI port are using them successfully with HDMI displays. so whoever is telling you that HDMI is not supported on an M1 Mac is FLAT OUT WRONG. I would try and find an Apple Store or an Apple Authorized Service Provider and see if they will help you with this. and since it's a new purchase, you could even try and Contact Apple for support and service to see what they have to say versus talking to Costco's "expert". all new Mac purchases come with limited telephone support.

sometimes, if you go to your display settings, you can use the "arrange..." options to arrange as an extended display, and then set it back as a mirror. and you can also try and toggle the "use as" options.

GOOD CALL Grant Bennet-Alder! I just checked that using Ventura. while in System Settings > Displays, when you press and hold the "option" key, the "Night Shift" button becomes the "Detect Displays" button.

Apple wouldn't spend the money to add a port that wouldn't work. so, before you return it, go into System Settings > Displays and press and hold the "option" key. you will see the "Night Shift" button become the "Detect Displays" button. and then click the "Detect Displays" button. I think that is the missing ingredient.

you spoke with a mistaken apple advisor. just because he has that title, doesn't mean he knows everything. nobody can know everything.

have you tried to use the HDMI output by connecting it to an HDMI display? it should be plug and play. but you may also need to correctly configure you display settings.

if you have tried it and it's not working, please let us know as there are a few things to try.

14-in MacBook Pro introduced in 2021 DOES have an Apple-Silicon chip on board.

it features HDMI 2.0, a very good version of HDMI that should, in itself, have no problems supporting an external HDMI display up to 4K at 60 Hz.

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to get a Mac display to become active, you need the Mac to query the display, and the display to answer with its name and capabilities. Otherwise, the display will not be shown as present, and no data will be sent to the display. "No signal detected" is generated by the DISPLAY, not by the Mac.

This query is only sent at certain times:

• at startup

• at wake from sleep — so momentarily sleeping and waking your Mac may work

• at insertion of the Mac-end of the display-cable, provided everything on that cable is ready-to-go

• on invoking Option-(Detect Display) button in Displays preferences (from another display)

so try doing some of those things and see if the display comes alive.

On older Mac OS, you opened

system preferences > displays ...

then held down the Option key and the (Detect Displays) button appears.

But if none of those others produced any suggestion that the display was present, an exchange may be the right approach.

then it does sound like a hardware fault, because there is no reason that it should not be working. maybe wait and see if Grant Bennet-Alder has any other suggestions.