Outgoing iPhone calls are being redirected

Your phone is not redirecting your calls.

If you have an entry in your contacts for the business you're calling that is experiencing the problem, verify that the number you have listed is correct.

If it is, report the problem to the business and to your carrier.

The phone system at the business may have been compromised.

Nope. It is NOT your phone.

Your phone does not have the ability to magically redirect your calls to different numbers.

So long as you continue to pursue that line of thought, you will not solve the problem.

Contact your cellular carrier.

For what you are reporting here to be an exploit or a “hijacker”, the exploit tooling involved is worth millions of dollars. You being worth millions to target and with a very well-funded adversary also places this discussion far beyond what help that can be offered here, for technical snd for privacy reasons.

Further, being redirected within the cellular network involves a carrier compromise, and that too places this further outside what help can be offered here.

Or there’s something else going on here, whether that is an Apple Account compromise with incorrect numbers stored in the Contacts list, maybe a generic carrier issue, or something else.

Problems with business phone systems are far from unusual, though those problems do not show as either incoming or outgoing and contemporaneous calls in the call list. (That inclusion of contemporaneous calls would potentially be evidence of issues, too.) Carrier call-handling issues are also not going to be addressable here. And the Cloudflare outage yesterday probably knocked some call-handling systems offline, too.

How long has this been ongoing?

What account security-related steps have you already taken? Two-factor authentication?

Have you reported the mis-routed (or dropped?) calls to the businesses and to your carrier?

Libre 3 is the name of a blood glucose monitoring system. If medical issues are potentially involved (and nobody here knows or can know that), check with your medical provider.