U2720Q, MacBook, no USB-C from your device, #3

I've been using a U2720Q monitor for 2 years with a MacBook Pro 2019 16' T2 connected with USB-C. About a week ago, the monitor shows this message when I connect the monitor to the MacBook: NO USB Type-C from your device and battery charging still works.

I've been in touch with Dell. My product is still under warranty, support sent a replacement monitor (refurbished, not brand new). At first, the new monitor worked. I disconnected all cables (USB-C, power cords) just to reorganize my station. After powering up the new monitor, same message: NO USB Type-C from your device.

• From here I've tested everything below on both monitors:
• No cables power button reset -> failed.
• Factory reset -> failed.
• Connect the Macbook with my USB-C cable to other brand monitor at a local reseller -> worked.
• Diagnostic the MacBook at the AppleStore: no hardware issue (usb ports ok, etc.)
• Try to connect to another brand monitor (not Apple…} at the AppleStore (with my USB-C cable and Apple Thunderbolt cable) -> both worked.
• Replace USB-C cable base on Dell's specs -> failed.
• Replace USB-C cable with an Apple ThunderBolt cable -> failed.
• Force USB-C on start -> failed.
• Auto detect USB-C -> failed.
• Switch from other sources to USB-C -> failed.
• SMC/PRAM/NVRAM reset with different cables -> failed.
• Erase and reinstall MacOS (in order to delete software settings) -> failed.
• Delete partitions, reinstall MacOS from scratch -> failed.
• Downgrade MacOS to Catalina -> failed.
• Reinstall MacOS 14.4 (latest update at this time), update Dell firmware from M2T104 to M2T105, SMC/PRAM/NVRAM reset -> failed.
• Tried with other computer -> failed.

Before latest OS update, on both monitors, signal worked with an HDMI to USB-C adapter (this MacBook has USB-C connectors only…). After OS update, the replacement monitor signal didn't work either with HDMI or USB-C. HDMI sill works with the old one. I sent back the replacement monitor to Dell support and kept to old one.

Dell didn't send other USB-C/power cord, with the replacement monitor, so I couldn't give a try with the exact same specs if this is a simple cable issue.

Apple support said that might be fixed with a firmware update.
Dell support said that's a compatibility issue with MacOS and the monitor.

I believe MacOS 14.4 release was between March 5th / 7th. Signal issue happened a day before and I can't say if the OS was already updated or not… At this time Dell firmware installed was the M2T104.

Is anyone faces the same issue with a similar setup? Is that known as a compatibility issue?

Thanks,