I used Ventoy. It's a free tool you "install" on your USB drive. Once installed, you can drag and drop one or more iso images to the drive and when you boot from the Ventoy USB drive you simply choose which installer you want to run. Windows installers will work automatically when you choose them and select the wimboot option. You can add as many installers as you want. Very awesome tool. For Linux, there's a GUI server shell script you can run to help you install Ventoy to the USB drive.