I know that you can use a L.V. tie to graphically connect the first note of additional repeat endings to a note that is before the first repeat ending (see below).
Is there a way to edit the playback so the note at the beginning of the second ending sounds tied?
Depending on the music, one can sometimes do this by suppressing the tied note in the second ending and extending the sound of the originating note in the Key Editor.
Because the first ending holds the tied note longer, I’m not sure it would work here, but you could try playing with it to see; perhaps a hidden note before the endings, doubling the first, that played only on the second time…
The tied-to note at the beginning of the second ending has its playback suppressed. The tied note in the first two bars has its playback suppressed on the second pass. There is a whole note in bar 1 in down-stem voice 1 which has its playback suppressed on the first pass, its voice column index set to zero, and its playback end offset set to 936. This offset is measured in ticks, and Dorico uses 480 ticks per quarter note. By setting this offset to 1.95 × 480 = 936, the playback of the whole note is extended by nearly two beats into the second ending.