I just wanted to share a puzzling thing I noticed on my iPhone that was on iOS 13.6 at the time I installed the new smart BASIC (v6). Smart Basic v5.8 was already installed on the phone when I downloaded the new version, which is its own app with the same name "smart BASIC". I noticed in my iOS settings that only one smart BASIC was listed, and its icon matched the v5.8 one. I was looking around in the settings because the ALBUM EXPORT command would cause v6 to crash... v5.8 had full photo album access (read and write), while v6 only had read-access (the setting actually read "Add Photos Only").
Updating to iOS 14 resolved the issue. Both smart BASIC apps were listed in settings and I had full read/write access to my photo album in v6. So if you're not using iOS 14, it's possible the same issue is preventing the new smart BASIC app from being listed when you try to share files in the Files app.