Twelve caustic sink ejections are not enough, when the mission gets rough.
Hmm… what is your ship’s boost speed? A fast ship should be able to get through the cloud with just 3–4 caustic sink ejections, provided that you keep boosting, manage to avoid the caustic generators (popping a heat sink before you boost past them helps), and don’t screw up the TG pulse neutraliser timing.
Turning off systems to reduce heat, and avoid detection worked briefly. You can eject heat sinks all day- sometimes you just run out of chips at the table. And always at the wrong time.
Do you have a beam laser with thermal vent effect? It is long-term more effective than popping heat sinks all the time (although the latter tend to be necessary, too.)
This clumsy noob did well to get even two hits on vents. Getting around to the other side, while being dogpiled, isn't much fun.
Pro tip #1: after you’re done with the two vents, pop a heat sink and boost to the core. Then 4 pips to weapons & keep firing your thermal vent beam at the core (or pop more heat sinks). And don’t remain stationary — keep moving around the core, and try to stick close to the Titan’s surface. (Yes, I realise this is a lot easier if you have a 6DoF setup.)
Pro tip #2: as soon as you’re done with the core, boost away until Thargs stop pursuing you (but not as far as the caustic cloud’s inner boundary). Then wait there for things to cool down, and use the time to synthesize more heat sinks. Don’t rush things — it’s OK to miss a vent cycle. The outer parts of the asteroid ‘cloud’ are very safe, solo (or in Mobius) you can go AFK there (I did several times).
Also: I do not recall you posting a link to your ship build; is it shielded or not? With Titan becoming increasingly aggressive, shielded builds tend to work better as they offer considerable resistance against the swarms. That said, shielded builds need a good deal of engineering and min-maxing in order to keep heat low.