Macbook Air M1 display randomly goes black (only backlight is on) and returns to normal after sometime.

Hard to say, but it sounds like a hardware issue of some sort with the laptop.

Trying to troubleshoot these more recent Macs, especially the M-series Macs is much more difficult. You need to have someone who is familiar with the M-series Macs physically examine the laptop to attempt to determine the cause of the problem. Even then, that person may have difficulty. This issue is probably beyond what anyone can assist you remotely because trying to talk you through some of things I can think of is beyond what I can do in a single post even if you are extremely technical skilled.

I have over 20+ years experience repairing Macs and I struggle with troubleshooting hardware/software issues with the USB-C Macs, especially the M-series Macs. An issue like this really requires a knowledgeable tech who is able to see the issue first hand, but even then they may have difficulty assessing the situation.

Disconnect all external devices to see if that makes any difference.

You can try a DFU Firmware Revive which resets the security enclave chip & system firmware theoretically without affecting the data on the internal SSD assuming the process completes successfully. Better yet is a DFU Firmware Restore which also resets the internal SSD & pushes a clean copy of macOS onto the internal SSD as well as the items Revive process does. Unfortunately this process requires access to another Mac currently running macOS 15.x Sequoia, but as of Monday, Sept. 15 it will likely require the host Mac to be running macOS 26 Tahoe which is being released on that day. Apple's OS requirements for the host Mac are inaccurate in the following Apple article (par for the course these days):

How to revive or restore Mac firmware - Apple Support