Using knob to set wifi password

I pulled out my old Boom and brought it up to the cabin.

As I was setting up the wireless networking, I struggled because the display is getting dim and wonky. Somehow, I managed to get the correct password in, but the next arrow was an additional space over, and I kept getting an error as I tried to connect.

I do not have the remote, so I'm just using the knob, and i guessed that the null space would be the one just to the "left" (one click counter-clockwise on the knob) of a lower case "a".

Well, now I somehow have 3 spaces before the next arrow, and I cannot figure out how to delete them.

i.e.
true password - Stay@TDL!>

my display - Stay@TDL! >

How can I "delete" those empty spaces and click next right after the last character "!"?

Or should I factory reset and try again from scratch? (if so, how to FR a Boom without the remote?)

THanks!