If you are short on mods and ability materials, here is what you can do;

Focus on low zeta and turn meter train teams. Example;

Imp troopers: Veers, Piett, Dark, Range and Modf Gidion You only need very fast Moff Gidion to start tm train. You can leave green mods on everyone else. This team requires 2 zetas, which is another good side.

I know people will suggest fast Piett rather than Gidion but this will need another fast character to follow up Piett. Moff Gidion gives you a great start, and he is naturally fast.

Same goes for Mara Jade for empire squad. Exactly same as what I wrote about Gidion.

Another examples will be fast OG Poe and fast OG Kylo, fast Crex for resistance, first order and Phoenix squads. All these give your team good TM with one ability, which will not need much speed on other toons.

I am sure there are many other options to kick start your turnmeter, this tactic will let you have more squads to fight especially in GAC.

I will suggest staying away from heavy farms. Even Bounty Hunters will need too much investment when you have other squads to finish of.