That MacBook Pro M1 2020 supports one display up to 6K at 60 Hz over ThunderBolt-3 (possibly with added adapters). no native HDMI port.
That Dell SE2722HX display appears to be a 1920 by 1080 display at 8 bits/color up to 75 Hz refresh.
connectivity:
HDMI 1.4
Analog VGA
When a modern Mac sees transmit errors, it drops the connection. More recent macOS is becoming more and more demanding that there be NO transmit errors. The most common reason for dropped display connection is sub-standard cables.
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.
HDMI was invented for HD TV sets. it works great at its original resolution of 720i or 720p. At higher resolutions, it quickly develops issues that are complex to solve, and the cables and adapters required to solve are NOT intuitive.