Unless, I'm completely missing the boat here, one could turn these two chords (and the subsequent passing chords) into an interesting groove, no?
For instance, using a "D" to get back to the Db Maj9 chord (instead of the Ab7 b9 #5 )
D/ Gb A C E
or
use a walkdown starting from the Fm9 to the Db Maj9 chord:
Em7 (E / G B D)
Ebm7 (Eb / Gb Bb Db)
DMaj9 (D / Gb A C E)
or
change the bass notes to the walkdown above; now you have a 3-6-2-5-1 progression:
Fm9
Bb / G B D
Eb / Gb Bb Db
Ab / C F A
Db Maj9
Whadda ya think?