Unable to enter recovery mode since failed bootcamp installation

MacBook Air 2018 (Intel) issue

Hello,

Let me tell you about a problem I have since yesterday with my MacBook Air 2018, which so far has been working fine.

I got it from my father-in-law who won't be able to use it anymore.

Since this model has an Intel processor, I wanted to install Boot Camp and Windows 10 on it, and since then the Mac has stopped booting. (I should tell that Bootcamp had never been used on this Mac before).

While installing Boot Camp (using the Boot Camp Setup Assistant) everything was fine, then an error occurred while installing Windows. No way to quit the Windows installer. So I turned off the Mac with the power button.

Then when I restarted the Mac, the screen remained black, with no "Bing starting", but with a small white wheel spinning for a few seconds. Then it restarts in a loop (black screen, no "Bing", spinning white wheel, black screen, etc.)

(The "Bing" I'm talking about is the sound of the Mac starting up, unrelated to Microsoft's search engine).

I did a PRAM reset, after that the loop became: "Bing", black screen with white Apple logo, black screen, "Bing", screen with white Apple logo...

Here are all the tests I ran on this poor machine:

- I tried to access the recovery mode (command - R) -> always the same loop

- I tried to access recovery mode via the internet (command - option - R) -> Bing, choice of network, download for 10min, then, at the end of the download, black screen, Bing, choice of network… loop

- I tried to access recovery mode via the internet and with the original system of this Mac model (command —option - shift - R) -> Loop: Bing, choice of network, download for 10min, then, at the end of the download, black screen, Bing, choice of network… in a loop

- Tried to boot in diagnostic mode (D on boot), still this looping reboot

- Tried booting in safe mode (Shift on boot), still looping reboot

Alternate start test:

- I restarted with the Option key, there I see 3 boot disks: The MacOS and 2 BootCamp Windows volumes.

- If I choose MacOS, I get the "Bing" loop, black screen with white Apple logo, black screen, "Bing", screen with white Apple logo...

- If I choose one of the 2 BootCamp partitions, generally it makes this same loop. BUT, sometimes it comes back to installing Windows, and there I can either quit the installation or continue the installation until the Windows error comes back.

- I created a Ventura installation usb key from another Mac (same generation, same OS version and Intel processor), I tested this key on this other Mac, the key boots perfectly . I have access to recovery mode etc. But when I want to boot with this key on my MacBook Air, I start with the Option key, I see the installation key, I select it but it doesn't go any further. The Mac restarts in a loop without ever displaying the recovery mode.

I've called Apple several times, but they don't have anything else for me to test.

Looks like the Mac is still in "Installing Bootcamp" mode and it can't finish this. Two things give me this impression:

- Booting with the Option key shows 3 volumes (1 MacOS and 2 BootCamp). The fact that there are 2 Bootcamp leads me to think that there is one that is temporary and should automatically delete itself at the end of the Windows installation (which does not happen)

- The Macbook turns on as soon as I touch its keyboard (strange?!?)

Who has an idea to explore?

Who knows the internal process of installing Bootcamp (by internal process, I mean everything that the Bootcamp assistant does without being visible (creation of partition, installation of Windows, etc...).

I'm pretty sure it's a software problem and if I take the Macbook to Apple I don't know what they'll do, but they might charge me for something I could have done myself.

I also don't want to pay for a part replacement (for example, changing the SSD, which of course should work. But the SSD is not removable, so I don't know what they will find to charge).

Thanks in advance for your advice.