Boot from the USB, choose "Custom: Install Windows only," and follow the prompts. Note that you cannot "downgrade" from a newer version (like 22H2) without a clean install if more than 10 days have passed since your last update. Windows downgrade - Microsoft Q&A
Microsoft maintains a download page where users can select specific editions. Sometimes, older ISOs remain accessible via direct links or the "Download Windows 10 Disc Image (ISO)" page if the browser user agent is adjusted to mimic a non-Windows device (though Microsoft has made this increasingly difficult). windows 10 1903 iso