If you can't find it on either Play Store or Galaxy Store then it's not available. I had the same issue with my Tab S4 and I wrote an email to the developer and created a review on the Play Store. Eventually they released one for the Tab S4.
If I recall correctly, I tried sideloading it and it didn't work, your mileage may vary.
Galaxy S21 Ultra 512g(VZW), Galaxy Book (original, VZW), Tab S8 Ultra, Tab S4, Galaxy Watch3(VZW), M8 Smart Monitor