Well, remember that you're allowed to relic 5 star toons to r3 or maybe even r4, I forget.
So it will definitely suck more using r3 against r5 than it did in the last couple conquests, but it will suck less than it did a year ago when you had to make them survive at gear12.
Also remember that the relic delta of R-2 is small (10%? 20%?). Sure it will be a little harder, but
- not that much harder, and
- you get to bring in r9 attackers to kill the enemy quicker, which also helps keep the new toon alive.
If you're struggling with "win X battles with Y toon surviving feats," one good strategy is to just not let the enemy take very many turns, and you can do that with this squad:
Maul (Lead)
Paz Viszla
Canderous (or support Mandalorian if you're using Zealous Ambition)
Wat Tambor
Toon Y
The idea here is that Wat gets a bonus turn at the beginning and gives out tech to someone (either Attacker tech to Maul or Tank Tech to Paz). Since giving tech is a special, that triggers Maul's Frenzy, so he gets a bonus turn before the enemy even moves. Use your opening volley to get things rolling on your side. When Canderous assists he gains TM.
If you have ramping damage or Amplify Agony (for Canderous' DoTs) or Zealous Ambition (use Armorer instead of Candy - you don't get the TM train, though, so this is best with 2XZA or more so you really kill them with minimal turns) you just take the enemy apart.
Note that this may not work against some enemies who have TM trains of their own. (Canderous will trigger the TM gain of a Thrawn lead, for instance, and the enemy Empire toons will quickly overwhelm you.) Against teams with no TM trains of their own, it's pretty reliable and doesn't require any GLs. If you bring Maul, Canderous, and Paz up to r7/r8 this strategy will even get you the advantage when relic delta kicks in.
Sure, I know you don't want to relic more toons than you have to, but all three of those toons are good outside of Conquest.