There are some options between min iLvl and unsynced. "Unrestricted>Level Sync" lets you be the appropriate character level, but you will have the maximum iLvl allowed for that character level. You can also combine this with "Silence Echo" to either keep it at maximum iLvl or allow for additional Echo boosts in power for surviving long enough in the fight. You can even do "Minimum IL" and keep the echo on so that you start at min iLvl, but get a bit stronger over time. The sync system still has its problems, but there are quite a few levers you can pull to change the difficulty of old fights without having to be incredibly weak or insanely strong.