Editing is Supremely Difficult

I'm a pretty new user of Chordify, and a Premium user.  While I am absolutely thrilled with the app's ability to "get close" to the chords in the song and know that it is enormously difficult to obtain 100% accuracy due to the dynamic nature of the songs, and I appreciate the ability to Edit a given song to make some fixes, it is ENORMOUSLY difficult to edit those songs.  I have a whole list of things that are difficult and very non-obvious:

You cannot change a minor to a major chord by simply typing the first letter.  Try changing Gm->G and it refuses to change it. You must type Gmaj and enter.  It took a while to realize I needed to do that.  I don't see why simply typing a G by itself couldn't replace the Gm.

Filling in a missing chord frequently deletes chords downstream from it.  This is maddening.  I fill in a missing one, and it deletes one lower in the music that I have to replace. Then THAT deletes one after it.

Sometimes a chord just simply refuses to be entered.  In the screenshot- it originally was a Gm.  I tried typing Gmaj and it disappeared.  What is weird is that I can change it to ANY other chord- a C, an F, a Gmaj7- all of those will take. But then if I go back and type G or Gmaj, it goes blank.  It simply refuses to put the chord that I want.

Those are the bugs... I also was going to try a Copy, but there is no indication of how to Paste, and copy without paste is quite worthless.  Ctrl-V does not work. And if I highlight the range below the copied cells, it just displays "Copy" again.

So to restate- I really love Chordify and it is taking me to the next level in my learning to play guitar journey. I like unusual songs that are not always easily available.  The song above is Sea Legs by the Shins.  The orignal is quite full of errors- and Chordify got me close enough to mostly master playing it, but I constantly make mistakes as I have to memorize all the errors and remember to not play those.  That is why I decided to try Edit, but though I eventually got MOST of the edits done (using a Tab from Ultimate Guitar as guidance), I never could add that circled blank spot above.  And while I did fetch what is likely to be corrected chords from Ultimate, the fact that Chordify has the Play-along player with actual YouTube videos that has helped me tremendously, is why I will stay loyal to Chordify.  But, the app could be much improved in the User Interface- particularly the Edit feature.