Another help with KoReader Request

I'm somewhat new to Koreader although I used it years ago.  After successfully installing Koreader on my Kobo Libra Color, I used it for several days, only to find I lost both the Nickel launcher and Koreader to what must have been a software update.  I reinstalled KFMon and Nickel launcher but  KoReader would not install.  Crash reports identify a mistake in the code that I couldn't find. I tried a more recent version of KoReader (v2026.03) but no go (also an error in the code).  I tried editing a known flaw in the version I was using (v2025), changing the .lua file to include this code:

local KoboMonza = Kobo:extend {model = "Kobo_monza" or codename == "spaBWTPV"
 isMTK = yes​

This also did not work.  ​Now I'm out of ​clues.  I'm hoping someone can help, I was so close to getting Koreader to my liking.  ​Oh, I should mention I'm also running Simple UI.