Stuck with windows 10

[Mlk7]

So i recently installed windows 10 on my main drive, and basically wiped everything on my mac, and left me with only windows 10
i tried booting it up with control + R to bring up recovery mode, sadly when i try to it wont work it will go staight to the startup manager where my only option again is to start windows 10.
I really dont know what to do to get back to mac os.

Specs:
Mac pro mid 2010
GPU: RX580 Sapphire (no bootscreen)
1 tb Samsung evo 860 ssd
1 tb wdc hdd

Hopefully someone can help me with my problem

 

[velocityg4]

You can create a bootable USB installer for macOS from Windows. Then use that for a clean install. Make sure the flash drive is setup as GPT not MBR. Check the steps further down in the guide on how to do so.

How to quickly create a macOS bootable USB on Windows 10 - Pureinfotech

Here are the steps to create a macOS bootable USB media (Ventura) with GPT partition support on Windows 10, 11, 8.1, and 7 to rescue your Mac.

pureinfotech.com

I don't think you can easily download the DMG for Catalina. So, here is Apple's page for High Sierra instead. Then you can mess around with stuff like DosDude1 patch or Opencore to get to Catalina and beyond.

How to download and install macOS - Apple Support

Download and install current or previous versions of the Mac operating system on compatible Mac computers.

support.apple.com