No idea on the current timeline. A few years ago I paper filed for a deceased. It took about 3 years to get the refund (which was received not too long ago). I sort of guesses there would be a delay, and the heirs agrees to not hold up the closing of the estate for the relatively sizeable refund.
(What used to be common) sense says there are fewer and fewer at IRS handling paper items, so it seems reasonable paper just means longer, especially if the old theory that anything with money to be collected gets handled first (open envelope, see refund or no balance due, goes in the "get around to it" pile.
Caveat, I do not file returns for a living, but I "hear" things which add to my own dealings.