There is a Final Space The Complete Seasons 1 and 2 Blue-Ray that has been out since August 2020. It's up for $24.99 on Amazon right now and in stock. You can also find it at Walmart, Target, Best Buy, and other stores. I'm not sure about when Season 3 of Final Space will come to DVD and Blue-Ray, maybe in the future, but there hasn't been any news about a Blue-Ray Season 3 yet.
You can buy both seasons for streaming viz Amazon Prime Video.
The link below is also an option.