Hi suzybeat,
Thanks for following up. I understand you're curious if apps are safe to download directly from the developer's website.
Check out the information within the following article on how the software will be checked for the Developer ID signature, and then notarized by Apple, so you can be confident there is no known malware contained in the app: Safely open apps on your Mac - Apple Support
"If you download and install apps from the internet or directly from a developer, macOS continues to protect your Mac. When you install Mac apps, plug-ins, and installer packages from outside the App Store, macOS checks the Developer ID signature to verify that the software is from an identified developer and that it has not been altered. By default, macOS Catalina also requires software to be notarized, so you can be confident that the software you run on your Mac doesn't contain known malware. Before opening downloaded software for the first time, macOS requests your approval to make sure you aren’t misled into running software you didn’t expect."
Further, macOS will notify you if it detects malicious software, and will ask you to move it to the Trash when opening the app.
Cheers.