booting Fedora USB ,'the version of macOS on the selected disk needs to be reinstalled'

Thanks for clarifying everything, that really helps.

In the Startup Security Utility try checking "No Security" to see if that makes any difference.

My mac is installed in my apple ineternal storage(HDD),and i can actually boot macOS on my computer

my linux experience is 3 from 1-10,i think using external disk to run linux would get more experienced than virtual machine,i used virtual machine before,runing the ubuntu

I'm really glad you chose to install Linux to an external drive instead of trying to dual boot on the internal SSD. It is always risky dual booting to the same drive with macOS. The only real difference between using an Linux in a VM versus bare metal is having to deal with actual hardware compatibility issues, firmware boot & dual boot issues, and not having access to the GPU hardware acceleration.

i thinks the Fedora may be compatible with 2019 macbook pro,my mac is x86 architecture,i installed .iso for x86

Do you know the person or group i could ask for the 2019 macbook pro system issue

The problem with the Apple USB-C model Macs from 2016+ is that they use some very unique & proprietary hardware which the Linux community is still trying to get working since Apple provides no technical specifications on how to communicate with their proprietary & unique hardware. The 2018+ Macs are even worse for compatibility because of the T2 security chip as well.

Like I said, I have no idea how compatible Fedora is with a 2019 Mac. All I know is that I have used Kubuntu 2020 on a 2016-2017 model (don't recall if I also did so with a 2018...would have been Kubuntu 2022 version if I had). I believe I have also booted Debian Sid within the past year on a 2018 MBPro as well. Kubuntu & Debian are related (Debian is the upstream source for Ubuntu/Kubuntu). While I could use the laptop, there was no WiFi support (I forget what else did not work). Fedora is completely different from Debian/Kubuntu even though they both use a Linux kernel, although that kernel may be configured differently plus I don't know what non-free drivers Fedora may include which will be required for some of the Apple hardware. I haven't done more than test boot Linux on the 2016+ Apple USB-C Macs.

These sites are the only ones I know which provide any status details on Linux support of the Apple USB-C T2 Macs from 2018-2020:

https://github.com/Dunedan/mbp-2016-linux

https://gist.github.com/roadrunner2/1289542a748d9a104e7baec6a92f9cd7

https://t2linux.org/

Outside of using Linux in a VM on a Mac, the next best option is to just use about any other 2007 - 2015 Mac (avoid the 2006 Macs), or just about any non-Apple PC (not the low end models since they barely run Windows). A non-Apple PC is the easiest way to learn about installing Linux on bare metal & dual booting. You may need this experience in order to understand how to deal with Linux boot issues before you will even have a slight understanding on how to deal with Linux boot issues on a Mac with a non-existent firmware interfrace. I know there have been times when I've had to customize the Linux bootloader in order to allow a Mac to boot a full installation of Linux even though the Linux installer booted fine because this is due to the Linux installer using a more generic bootloader while the full Linux installation uses a customized bootloader which some Macs may not handle without some intervention (also occurs with many non-Apple UEFI PCs as well, but at least non-Apple PCs have a BIOS/firmware interface which can help get past this issue).

To know whether the version of Fedora you have is compatible with a 2019 Apple laptop would be to check with the Fedora community. Or how compatible and what specific things you may need to do for getting Fedora to work properly on the Mac. At best you will only get some generic advice on the Apple forums in relation to Linux support in general on Apple bare metal.

I think a picture of the whole screen may be needed.

So this occurs when trying to boot an external Fedora USB installer, or trying to boot a full Fedora installation from an external drive which you already installed onto the external drive? Were you also successfully booting a full Fedora installation from the external drive before this issue occurred or are you trying to boot Fedora for the first time from an external drive?

I feel there are some important details missing here. Keep in mind I have no idea about anything you have done to this laptop, nor its current configuration except for what you have posted here.....I'm still a bit murky on your current setup including whether you are trying to install Fedora or if Fedora has already been installed (if the latter, has it ever booted?).

Have you modified the laptop's security settings using the Startup Security Utility to allow booting from external drives?

Is macOS still installed on the internal SSD and you can actually boot macOS on the internal SSD?

Perhaps you need to "Restore" the firmware which will reset the laptop's T2 security chip after which you will need to reinstall macOS from Internet Recovery Mode followed by using the Startup Security Utility to allow booting from an external drive.

I have never tried using Fedora on a Mac. Are you sure Fedora is compatible with a 2019 MBPro? Linux support in general is still lacking for the USB-C Apple laptops so I'm not sure whether Fedora is configured to work with an Apple USB-C laptop (especially a T2 model).

I'm thinking when you select your Fedora USB it is not able to boot so it then trys to boot to macOS (or it is trying to boot into Internet Recovery Mode in order to have you use the Startup Security Utility to allow booting from an external drive).

These 2018+ Mac are much more difficult to work with and have a lot of quirks.

I have successfully booted an Kubuntu 2022 USB installer and installed Kubuntu to an external drive without any issues. I don't recall if I used a 2016-2017 model, or whether I did so using a 2018+ model. I know I have not had any luck booting my external Debian Sid USB drive to a 2020 iMac yet (I haven't had time to do any troubleshooting). Perhaps you should try Kubuntu first to see what happens. Some Linux distributions do have trouble booting some older Macs and requires some manual tweaking of the bootloader sometimes. I don't know how much Linux experience you have in general.

Is there a reason you are not installing Fedora into a Virtual Machine?

Where & when are you seeing this error message?

Were you dual booting Fedora and macOS from the internal SSD?