Seven months ago I posted A Case Against Strong Longtermism on the forum, and it caused a bit of a stir. I promised to respond to all the unaddressed comments, and as a result, have produced a four-part "sequence" of sorts.
The first and last post, A Case Against Strong Longtermism and The Poverty of Longtermism deal with longtermism specifically, while the middle two posts Proving Too Much and The Credence Assumption deal with bayesian epistemology, the iceberg-like structure keeping longtermism afloat.
The subsections are listed below and don't need to be read in any particular order. Special thanks to Max Daniel, Jack Malte, Elliott Hornley, Owen Cotton Barratt, and Mauricio in particular, without whose criticism this sequence would not exist.
Now time to move on to other subjects...
I think that some of your anti-expected-value beef can be addressed by considering stochastic dominance as a backup decision theory in cases where expected value fails.
For instance, maybe I think that a donation to ALLFED in expectation leads to more lives saved than a donation to a GiveWell charity. But you could point out that the expected value is undefined, because maybe the future contains infinite amount of both flourishing and suffering. Then donating to ALLFED can still be the superior option if I think that it's stochastically dominant.
There are probably also tweaks to make to stochastic dominance, e.g., if you have two "games",
then one could also have a principle where Game 1 is preferable to Game 2 if X > Y, and this also sidesteps some more expected value problems.