Can I connect Mac mini to iPhone 11 via Bluetooth?

Bluetooth pairing an iPhone or iPad and a Mac is not supported. 

If you are attempting to use Handoff/Continuity or AirDrop, that does involve Bluetooth but the devices are NOT paired; Bluetooth just needs to be on and the devices in range of each other. The following may help with Handoff/Continuity issues: Continuity features and requirements for Apple devices - Apple Support

Also see Share files between your Mac and Bluetooth devices - Apple Support

And see the information in: Bluetooth: Why can't I pair my iPhone or … - Apple Community

That is correct. iPhones do not connect to Macs using Bluetooth.

You told us how you’re trying to do something - using an impossible method. If instead you tell us what you’re trying to do, we can very likely assist you.

By the way, you should immediately update iOS as you’re missing some critical security updates.

As you can see in the article I provided, there is absolutely no need to have an iPhone connected to your Mac if Apple Pay is properly set up on your Mac.

So we’re missing some other pertinent information about your scenario.

See this.

Use Wallet & Apple Pay on Mac - Apple Support

Kentucky Charlie wrote:

Of course, I used this initially when I first used Apple Pay.

Might this be considered "condescending"?

Glad the discussion is concluded. Enjoy your Apple gear.