I have the same software issue as you do, and there are others on the Boost and Sprint Network that have the same issue, but the reps will tell you that it is your device and to contact Samsung, which in turn will tell you to bring in your phone to one of their locations or to send it, all of this just 'cause Sprint wanted to be the 1st carrier to release the Android 9 update, instead of making sure that the system was bug free.
Take your phone to your local ubreakifix store and have them downgrade your phone to Android 8 (Oreo), once they do that, do a carrier reset (Dialed ##72786#) and that should fix your phone, it fixed mine. But remember to do a full back up, so once is fixed you can restore all your stuff. By the way they didn't charge me anything to downgrade. Hope this helps.