Huawei does have some espionage in their history and Chinese phones usually do contain questionable features. The now-dead ZTE Axon 7 has "MFVKeyguard" that's completely hidden from ZTE's apps and permissions lists. Chinese phones always come with a "Weather" app that wants to track your location even when you're not using it. It would be no shock if cell tower hardware came with extra services or "accidental" vulnerabilities.
Likewise, don't buy cell tower hardware made by Google, Amazon, Microsoft, or Apple.