It would be highly interesting to read something in depth on Twain's ultimate religious views. There's clearly very much in his viewpoint and manner of expression that is Epicurean - adjacent.
And yet there seems to have been a failure to take a few steps further that would have made him more consistent from an Epicurean point of view. I don't know why he failed to go a little further and it would be an interesting study to explore why. As an example maybe in the end he saw himself more as an "entertainer" than a real "social reformer" or "phllosopher." I haven't read nearly enough of his overall work to have a basis for a firm opinion.
This subject came up briefly in the Wednesday Zoom last night and I could not even remember the name of the book or work by Twain that we discussed some time ago as being arguably Epicurean-adjacent, and Joshua was awol ( ) and could not remind me!
So here it is -- something that would definitely fit into a discussion of this topic -- What Is Man?
RE: Episode 210 - Cicero's On Ends - Book Two - Part 17 - Self-Approval As Pleasure
https://www.gutenberg.org/files/70/70-h/70-h.htm

Definitely questions of what is actually "Epicurean-adjacent" vs "the camel of virulent anti-Epicureanism has his nose under the tent" are always of interest.