It doesn't help you diagnose and fix your issue but based on my experience as an ex-software engineer who understands a little of how ECUs work, I would be hesitant to let anyone do anything to the ECU software to make an OBD2 error go away and similarly hesitant if someone says they can diagnose and fix ECU hardware (very few people know enough about electrical engineering to fix them). And in my experience as an amateur mechanic who breaks things all too frequently and then only has OBD2 error codes to diagnose the issue, the error code is just the point where the ECU spots that something is wrong but very rarely points to the issue and always should be evaluated with a good sceptical mindset.
Software doesn't deteriorate over time like hardware does so assuming it's not a bug that was fixed in a software update (usually done by a dealership as part of a recall or service), modifying the software to accept values out of it's acceptable bounds will just hide the issue but doesn't deal with the issue itself.
Either that error code is rarely used by the ECUs of other manufacturers or they rarely encounter that issue because if you Google just "P2308", most of the results and the almost all the video results are for Jeeps/Dodges/Chryslers.
Do you know what indicated that the ECU was the cause of the issue?