Depends on how strong your team is. If your whole squad is G12 it’s a breeze anyway, zaalbar can take hits for roughly one eternity and mission zeta helps keep him healed (mission basic heals Z). Took me 2 tries only because of the typo in Malak’s gnawing terror. All those characters are fantastic investments anyway so it’s not like your bumping up Geo Spy for Padme or something.
shouldn’t be a big deal either way and you’ll get way more value out of mission in TW/GA with the zeta in the interim, go for it