Yes, undervolting can cause all of that.
 
That is the exact crash reason I get when I'm pushing either my clocks too high, or too high of an OC with an undervolt, it will list that (either LiveKernelEvent 141 or 1a1) for Port Royal's reason for crashing, as well as drivers if they crash.
 
It's silicon lottery on whether or not one card to the next can run the same undervolt.  1905MHz @ 900mV is not too too rough, I think mine did 1890MHz @ 875mV so pretty close.
 
I would hammer the card at stock if I were you, then pop on a sensible & effect OC/Undervolt, ensure it's good to go at stock first so you don't have to worry about it dying on you later (hopefully).  
 
You have every right to be paranoid/concerned, but in reality, you don't need to be.  You SHOULD expect your hardware to JUST work, when it doesn't, it can be a pretty traumatic experience especially when something full on dies on you, when you're new to computer stuff.  I remember the first time I had a liquid loop leak :-D Good times.
 
But yeah, test the card at stock, put it through the ringer, then fiddle with an undervolt for more efficient/effective daily use...
 
Or you can go crazy & test something like your card's equivalent to this:
 


 
:-D
 

RDR2 is picky period from what I've heard.  I don't own it (yet) so can't comment.

1905Mhz at 850mv+500 mem running absolutely smooth max temp never exceeds 65c usually floats between 55 and 60. No crashes. (OC bios switch/ 3080ftw3). I could run this with silent bios for more silence but PX1 was acting all sorts of crazy so I just set to OC bios ignored PX1 and just load the MSI AB profile every time and GG.