Generally speaking, your options with an Android phone are to use the OS that comes with the phone or to use a ROM you download from the internet. An iPhone gives you fewer options, of course (just stock).

New Android phones often lack alternative ROMs and ways to conveniently install them. Phone manufacturers often use hardware drivers that aren't in AOSP, the main open source version of Android, so people making their own ROMs often have a lot of work to do.

I would recommend doing careful research on the availability of images and ways to install them on that particular phone. If nothing is available, you might be stuck on the stock OS indefinitely (might noy be a bad thing, I don't know how Huawei does things).

I would look into LineageOS in particular. They're the main group making trustworthy aftermarket ROMs ans guides.