Diesel Bombers - 2018 Duramax Lemon

New to the forum and hoping for some help. Won’t get into the long story of the problem, just need some help trying to avoid getting screwed. Had purchased an extended warranty at 144k miles that required 5k miles to be driven before warranty kicked in. At roughly 148k, less than 300 miles before I hit the required 5k for warranty to kick in my 2018 3500 had a major engine failure and the repairs are 20k. Normally don’t try to screw the system but I am over 2k into payments on an extended warranty I can’t use because I fear that when the CEL registered a problem it time stamped it. Question is, if anyone doesn’t feel bad about helping me claim this on a warranty, does the 2018 duramax CEL time stamp mileage and date with the ECU? If so, if I were to replace the ECU with a new stock version now that it is over the 5k requirement, would it record the new time stamp on that ECU after replacing with a new one. Like I said, hate screwing anyone, just done with this thing and all the problems it has had since buying it new. Any help would be appreciated.