Those double sided brushes are garbage in my opinion. I'll link a few things I've bought from Amazon to use on my dog at home. Brushes are going to depend on the coat of your dog.

Undercoat rake - this is the exact one I have. Used on both a corgi and a border collie mix

https://www.amazon.com/Maxpower-Planet-Pet-Grooming-Brush/dp/B07P2N8HQH/ref=sr_1_5?crid=2P8HEZWF6NSSI&keywords=undercoat%2Brake%2Bfor%2Bdogs&qid=1649195965&sprefix=undercoat%2B%2Caps%2C116&sr=8-5&th=1

long pin slicker brush (they come in different pin lengths. I like this one, I use an Artero at work though.

https://www.amazon.com/Show-Tech-Transgroom-Tangles-Slicker/dp/B00TYEMIK8/ref=sr\_1\_5?crid=9CKEBVE22HDA&keywords=long+pin+slicker+brush+for+dogs&qid=1649196046&sprefix=long+pin%2Caps%2C113&sr=8-5