Need download for Garage Band for mac OS Big Sur 11.6.1

Hello TBRNTTB,

Welcome to Apple Support Communities. 

We understand that you want to know how to download a previous version of GarageBand. We are happy to help.

We recommend downloading apps from the App Store on your Mac using the steps here: Download apps from the App Store on your Mac - Apple Support

"How to download apps for Mac

1. Open the App Store app.
2. Browse or search for the app that you want to download.
3. Click the price or Get button. If you see the Open button instead of a price or Get button, you already bought or downloaded that app.

In the App Store, if an app has a Get button instead of a price, the app is free. You won't be charged for downloading a free app. Some free apps offer in-app purchases and subscriptions that you can buy. Subscriptions and in-app purchases give you access to more features, content, and more. Learn more about in-app purchases and subscriptions."

If the GarageBand version in the App Store is not providing the 10.4.1 version, then check your Purchase History. If you've previously downloaded that version of GarageBand, you'll find it there. Then you can redownload it.

View your purchase history for the App Store, iTunes Store, and other Apple media services - Apple Support

Redownload apps and games from Apple - Apple Support

Let us know if you have further questions.

Take care.