A good temporary replacement for gear

Mods effectiveness are increased by gear level. You would get some amount of help by focusing on zetas/mods, but to really do need the gear.

For instance offense primary increases offense by X%. the higher your offense from gear, the more damage you gain from the mod

That being said, some characters need it more than others. Pay attention to how the team does in raids, and prioritize your gearing to fix the teams weak point. If your team is staying alive but not doing much damage, focus on your attackers' gear first.

Tank keep dieing early on and your squad gets word before enrage? Focus on gearing up the tank first. Etc...

Zetas are not temporary and I would never zeta a toon that was not geared up to a useful level.

Zetas can make or break a teams synergy, but this is not always the case. That is something you need to decide when making the team and who to zeta.

Mods are transferable so they can always help make a toon better, but mods are not going to really overcome anything. I mean to say, that a mod placed on a toon is a compliment to their skills and stats, but as stated above will not help you make a g8 toon better than a g9 or g10 of the same toon.

It may be more helpful if you give examples of what you are thinking. Which toons, which zetas, what arr you trying to achieve.

Mods, IMHO, are the most important part of the game and can replace or exceed gear in some circumstances.

In the last GA I beat a number of 3 and 4 zeta g10-g12 teams with 1 or 2 no-zeta crappy g8 squads. If the average speed on one team is 140 and the average on the other is 190, the faster team will usually win if you are smart about who you kill/stun/ability block/daze with your "free" opening moves. Take out TM engines or keystone characters at the start and you can win over superior teams. Vader, Sith Assassin, FOO, Kanan, Rex, OG Chewie, Vandor, GMY, etc are examples.

Getting disruptors like Boba or Vet Han or Vet Chewie or Nest or Palpatine to get their AOE off first can win the match. Or making your own engines to go first can do the same.

In short, put AT LEAST a speed arrow on each of your characters. Everytime You see one in the mod shop, buy it, max it and slap it on your engines or disruptors. Then damage dealers or tanks. You can't have too many. This simple thing will win you a lot of games in GA and TW over "better" teams with more zetas and gold rings.

My personal goal is to get an average of +50 speed on my top 12 squads. I'm close.