MacOS – Question marks folder when I turn on the mac

I recently tried to reinstall macOS on my MacBook Air 2017 (Catalina) because it was slow and full of problems (for example, I didn't have any disk space though I had deleted and uninstalled everything).
So I started to follow a tutorial: I launched my device by going to my mac recovery, "Disk utility" and I deleted all the data in my Macintosh disk.

I don't know why, but my mac turned off. When I turned it back on, I saw a question mark inside a folder.

So I turned on my mac again, and I pressed CMD + r. I see a progress bar with a planet. It seems to work for now. But after that, when the progress bar is loading with the apple logo, there is a startup sound, the screen becomes completely black, and it comes back to the question mark inside a folder.

I also followed this tutorial. The unique difference is that I press alt rather than cmd + r. I select my wifi, and the downloading of the OS seems to work again, but still the same issue.

Here is a video of the issue.

I tried again and again, the same thing happens everytime, at the same level of loading.
I already tried to reset the NVRAM, but it changes nothing.

If you have a possible solution to share me… thanks !