(Windows)
git clone https://github.com/ppy/osu
cd osu
dotnet workload install android maui-android
dotnet publish -c Debug --runtime linux-arm64 (for pi-apps you'll use release, I used debug for debugging)
(Saved location)\osu\osu.Desktop\bin\Release\net6.0
Copy over linux-arm64 folder to the pi


(Raspberry Pi)
sudo apt install 7zip
sudo apt install libsdl2-dev
https://www.un4seen.com/download.php?bass24-linux
go into \bass24-linux.zip\libs\aarch64 and copy the libbass.so to /usr/lib
https://www.un4seen.com/download.php?z/0/bass_fx24-linux
go into bass_fx24-linux.zip\libs\aarch64 and copy the libbass_fx.so to /usr/lib
https://www.un4seen.com/download.php?bassmix24-linux
go into bassmix24-linux.zip\libs\aarch64 and copy the libbassmix.so to /usr/lib
/home/pi
git clone --recursive https://github.com/veldrid/veldrid-spirv/
cd ext
./sync-shaderc.sh
mv src shaderc
cd ..
./build-native.sh -release linux-x64
cd build/Release/linux-x64
mv libveldrid-spirv.so liblibveldrid-spirv
sudo cp liblibveldrid-spirv /lib/aarch64-linux-gnu
/home/pi
mkdir libs
cd libs
wget https://chromium.googlesource.com/android_tools/+archive/20ee6d20/ndk/platforms/android-21/arch-arm64/usr/lib.tar.gz
7z x lib.tar.gz
7z x lib.tar
sudo cp libandroid.so /lib/aarch64-linux-gnu
sudo cp libdl.so /lib/aarch64-linux-gnu/
sudo cp liblog.so /lib/aarch64-linux-gnu/
sudo apt-get install libstb-dev
add kernel=kernel8.img to /boot/config.txt
sudo reboot
cd (wherever you have osu)
chmod +x osu\!
LIBGL_ALWAYS_SOFTWARE=true ./osu\!
stop the game from loading after the fonts load (ctrl + c)
nano ~/.local/share/osu-development/framework.ini
change "WindowedSize" to 640x480
chnage "FrameSync" to Unlimited
change "WindowMode" to Windowed
save the file
LIBGL_ALWAYS_SOFTWARE=true ./osu\!
osu should load in at 640x480 windowed