Does the holographic principle contradict eternal inflation?
There is no obvious implication to re-assess the large-scale topology of the universe.
You can still stereographically project infinity to a point on a sphere, if you need.
Implications to the holographic principle aren't immediate, at least.

When talking about objects beyond the cosmic horizon, it's a difference, whether we talk about observation or mathematical models. When talking about mathemetical models of the universe, it makes sense to talk about space and objects beyond the cosmic horizon, because we can get a higher symmetry of the theory. We can use mathematically simple structures like de Sitter spaces as simplified models of the universe, with no need to add an observer to the structure.

For an evidence-based science it's of course an extrapolation far beyond immediate observation, hence questionable. But there is also no evidence-based argument to assume, that the universe looks fundamentally different from a distant observer with a different cosmic horizon overlapping with our cosmic horizon, but reaching beyond.