Does a blocked extra point count as a missed extra point? This was the case in last Monday night's game when Justin Tucker's extra point was blocked and from what I understand it was counted as a miss but in other instances blocked kicks were merely considered blocked and not missed.
In NFL statistics, a blocked extra point is counted as an extra point attempt, so long as the end result is no points scored for the kicking team. From the NFL Guideline for Statisticians:
Whenever a player placekicks or dropkicks a ball in an attempt to score an extra point, he shall be credited with an extra-point attempt and, if the kick results in a point, with an extra point.
If an extra-point kick is blocked and the ball does not cross the line of scrimmage, and the offense recovers the ball and scores, credit it as a successful two-point conversion in either the rushing or passing category, depending on how the offense scored. Do not record a blocked kick and do not credit a defender with a blocked kick. If the offense does not score, do not record a two-point conversion attempt. It is a blocked extra-point kick.
Note that in statistics, no differentiation is made between blocked and simply missed kicks - for example, in the statistics for BAL at CLE, 12/14/2020, Codey Parkey missed an extra point Wide Right, and Justin Tucker had an extra point blocked; both appear identically on the stat sheet for the respective kickers, the only difference (outside of the play by play) being a player being credited with a blocked kick in the latter case.
As a side note, this is not an unreasonable way to approach kicks; the kicker bears at least some responsibility for blocked kicks, as their angle of approach determines the likelihood of a "normal" block (meaning, the ball sails over the line and someone reaches over and deflects it). Obviously some blocks are more the responsibility of the line failing to block someone, and the defender should be given some credit as well in many cases, but the kicker does have some control over blocks.