MacBook Pro can't use more than 1 external monitor at a time

That first screenshot shows you running a monitor at a refresh rate of 240 Hz in Retina “looks like 2560x1440” mode, where the Mac draws on a 5120x2880 canvas.

The support article to which you linked says that you can have only one external monitor, total, if you are going to be driving a monitor at 240 Hz. You may need to force that monitor to use a lower refresh rate (if the monitor has controls for doing that), if you want to use another external display at the same time.

Those displays at those high data rates are at the high end of you ability to drive them with either HDMI or Thunderbolt-3.

In order to be successful with a modern Mac running recent macOS, your cables must be absolutely top specs, and not overly long.

HDMI cables you want for HDMI-only Displays (higher resolutions than 720p TV sets) are marked as Certified with an anti-counterfeiting tag and are labeled:

"PREMIUM High Speed HDMI cable" or that + "with Ethernet" (up to 4K at 30Hz) --OR--

“ULTRA High Speed HDMI cable" or that + "48G" (supports higher resolutions and backward-compatible)

Cables with No Certification tags are good for your standard 720p TV set, and not much more.

so for HDMI for this application, you need certified ULTRA high speed cables, and nothing less will do.

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if using Thunderbolt-3 cables, they are generally limited to 0.5 meters maximum. Apple sometime packed a pre-engineered special cable as long as 0.8 meters in the box. To use at longer lengths, you would need a much more expensive (starts at US$125) ACTIVE Thunderbolt-3 or -4 cable.

Because your M3 Mac can not support Thunderbolt-5, obtaining Thunderbolt-5 cables is a waste of time because for this application, they perform no faster.

You did not indicate which display you are trying to use with which interface.

You could also try using the Refresh Rate popup menu in Displays Settings to reduce the refresh rate from 240 Hz to 144 Hz or less.

The Mac does not rely on Windows-like side-loaded "Drivers" which are actually packages of resolutions and settings for a specific display. Instead, it goes straight to the immutable source -- it asks the display itself.

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

• hold the Option key while you click on the (Detect Display) button that will appear in Displays preferences (from another display)

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

<< these 2 monitors work together on windows at max potential without any issue, Idk if that's relevant or not. >>

Not in the slightest.

The Apple standard for its built-in hardware-accelerated displays, makes them suitable for full-motion video for production/display of cinema-quality video with NO dropped frames, and NO dropouts or partial-blank scan lines due to memory under-runs or Transmit errors due to low-spec cables.

These acceptable settings are obtained by a query to the display itself. In most recent versions of MacOS, no transmit errors are tolerated, or the display will drop out.

Under Windows, you manually choose the settings you prefer, or download a popular "Driver" (which is actually a package of resolutions and setting thought to be good ones). Whatever happens is your problem.