Ignoring the technological limitations, the idea of uploading our minds into hardware in any scenario is pretty much the same as ending the human race. We would not be human anymore in any practical sense. Thats also not considering how much of our mental state is driven by chemical activity in the body, from hormones to adrenaline. It may be how we survive in some form, but we would not really be human anymore and its highly unlikely we would think like humans, either. This might be the way forward, ultimately.
I would want to stipulate that
until technological limitations can be conquered -- maybe a century, maybe 500 years, maybe 1000 -- you are correct, which why we should not fool ourselves, or else the "cybernative blunder" will be our great filter lol!
FTL being impossible and life between spread apart too far to contact each other before destruction is the most common explanation for a great filter.
This is where I end up. The expanse of both space and time are just real hard limits -- for beings such as ourselves. And then I add to that, that any species evolved enough to conquer those hard limits are so beyond my comprehension that I
cannot assume they would want to "contact" us. The result is: no wonder we are sitting out here in the coldness of space.
But we are working with a few diff ideas of filter now.
1) OP's original filter problem: will we "begins rewarding behavior that existencially destroys the host." A species filter of species self-annihilation
2) external filters, like an asteroid, or the dreaded corona virus which shall surely kill us all, or Angry Jesus.
3) filters which explain "where is everyone?" -- i.e., why it is to be expected we have not and likely will not contact life from distant (in time and space) "advanced civilizations."
4) filters which simply "cull" the system either up or down. Like maybe we will return to retardation for hundreds of thousands of years. From stone age to the moon and back, in 30,000 years, not bad. Call these "systemic" filters, because they represent significant evolutionary turns. Like the invention of fire.
I guarantee you there were tribes that could not deal with it. They died out or were taken as slaves or eaten as prey. Or modern tech. There is a reason silicon valley executives do not allow their own children to own the devices they make. They fear they are creating evolutionary downcullers.
So 4 kinds of filters. existential, external, cosmic, evolutionary. Or make up other words. The cosmic one is silly.