There’s no possible way you will live ten trillion years without the human brain becoming well-understood and upgradable.
So you’re worrying about an impossible scenario.
So you’re worrying about an impossible scenario.
That's a pretty big assumption to make. Science and tech seem to improve as a direct function of energy available, and in the past few centuries that has been increasing very rapidly (I'm not sure I'd say exponentially though). However we're clearly hitting limits both in regard to human more energy we can harvest as rapidly and the consequences of unsustainable energy usage.
How human would I be then?
There are many and varied problems we'll be facing. I just don't think "Immortality without any of the supporting technologies" is one of them.