Shutting off at low revs

Hi everyone! I bought my 2020 wr250r used about a year ago and when I was replacing the taillight recently, I found that there was a mouse nest in the air box and the mice had chewed many of the wires to the ECU. None of them were chewed through completely, so I taped them because there wasn't enough wire at the end to hardwire extra wire on. It had been running fine, until this week. It's now shutting off at low revs mostly in first and second gear. A neighbor told me that it's probably the spark plug but that doesn't make sense to me and I'm thinking it's a sensor connection to the ECU. Any ideas how I can fix this/replace the ECU? Any thoughts on whether it's the spark plug? Thanks!

Is the bike throwing a Fault Code?

Have you tried looking into the obvious, whether the chewed wires are shorting either with the frame or between them?