Unless this google certification is stored in hardware, that's not the case. You can flash Android phones with a custom bootloader, use that to flash AOSP (open source core android)/LineageOS, and for most people doing that the next step is to flash gapps on top of that.
locked bootloader in huawei I think, even if they open it it's not really a normal sideload and will be hard enough to not be a generally applicable solution.
I've got root on my Huawei P10 lite since day one (would have returned the phone if it were closed), not sure where you got the idea that unlocking the bootloader is not possible.
Here's a popular gapps distribution: https://opengapps.org/#aboutsection
Google's requirements mainly apply to OEMs bundling gapps into their stock images.