When I got a new phone last year, I purposely got a Pixel (open box 9a) to put GrapheneOS on it immediately. Been happy living the de-Googled Android life since.
I was sad that I had to go through the OOBE setup on the stock image to unlock the bootloader. At least it doesn't force an internet connection and login, unlike Windows.
While the OOBE of the stock image doesn't force an Internet connection, the ability to unlock the bootloader does - whether you can do it or not depends on the phone manufacturer's desire, and Android for some reason uses an Internet connection to check that.
My understanding is that it is impossible to unlock the bootloader on a new recent (Android 7+ at least; possiblt earlier) Android phone until it has connected to the Internet. After that, the ability to unlock the bootloader is permanent.
Is it possible to install basic Google apps like Gmail, Calendar, Maps, Drive without googlifying the whole phone?
I'm not looking to fully de-Google but I want Google as apps and not my OS.
If it's any consolation, the wipe* requirement before unlocking the bootloader is generally a good thing, even if it's inconvenient. Someone who is targeting your personal data gets access to your encrypted phone, either by stealing it or in an evil maid situation. They unlock the bootloader and install privileged code that helps them recover the symmetric encryption key or intercept your PIN. Then they either have your data or wait for you to enter the PIN. In theory recovery shouldn't be possible (access to the key depends on a secure element that rate limits brute-force attacks), but security bugs do happen. Wiping* your data before removing the bootloader's signing requirement is an extra layer of protection.
*It doesn't actually wipe your data; it just destroys the symmetric key, making the data permanently unreadable.