In 2008 there was a scandal about how every software contractor (including the likes of Microsoft, IBM and Oracle) working for the US government had a rootkit installed on all their systems. In 2020, there was a scandal on how people just pretended to remove that rootkit and had been covering it up since the earlier scandal.

The US intelligence agencies claim it's from Russia, but those agencies always claim it's from Russia. Since 2020 the press just stopped talking about it, with no hint of anything being solved.

Nobody needs intentional back doors.