earn 15 emblems of iridescent quality whats the best way?

Play Legion 😉 one of the best killers at gaining emblems.

Legion

git gud 🤡

Jokes aside, I second @twistedmonkey, play Legion with some slow down capabilities (e.g. ruin + pop) and abuse their feral frenzy power to hit as many survivors as you can.

That's basically a guaranteed iridescent chaser, but for the other 3 emblems.. well, it depends on you.

Repairing 2 generators solo is one way to get an Iridescent Lightbringer emblem, yes. I would say that Lightbringer is probably the second-easiest survivor category to do well in, surpassed only by Benevolence, in which you can get an Iridescent emblem just by unhooking two survivors safely and healing one of them.

I think it's a bit harder to get iridescents as killer.

• The easiest emblem there is the chaser (i think) - all you need to do is get into as many chases as possible and end them as quickly as possible. Stealth killers are best at this, as you can easily get your first hit in less than 10 seconds. Don't commit to long chases, as that hurts your emblem.
• Gatekeeper is annoying to get, as you'll need to adopt a pretty boring playstyle. Ruin or corrupt intervention and pop are your safety nets
• The other two are a bit inconsistent for me personally.

Survivor is easier.

• For lightbringer just do the equivalent of 2.5 gens and you'll get the iridescent. The best way to ensure a decent amount of time to work on gens in the beginning of the trial is to see where your teammates spawned at the start - if you're all nearby it means that the killer spawned on the other side. You know he'll be heading towards where you spawned, so run towards where you think he spawned and do a gen there (try not to get spotted on your way). He's almost guaranteed to find one of your teammates first, giving you free reign over gens for the first 1-2 minutes. If you spawned on your own, most of the time you're safe to do a gen there.
• For benevolence i think you need about 2 safe unhooks and 1 heal. Yo'll randomly get some protection hits throughout the trial, which helps. Once you're done genrushing, just try to help teammates as much as you can (saving, healing, taking hits, etc.)
• For evader - this is difficult unless you're a good runner. Getting into a few chases and losing the killer without getting hit will give you points in this emblem. The longer the chase, the higher the points and the more likely you'll get iridescent
• For survivor (i forgot the actual name of the emblem), you need to escape without getting hooked - this one is pretty difficult. I wouldn't worry too much about trying to get it as it will keep you from completing the ones that are easier to get - you can get the other 3 without even surviving the trial

EDIT: For the evader emblem as survivor you don't actually have to lose the killer - just force them to drop chase - i.e. try to create distance and lose line of sight as often as possible

I believe you only need to do 2 gens for Iridescent Lightbringer, as long as you do them solo. You can also do 1 gen and 5 dull totems (or less if there are hex totems - a hex is worth about 2.5 dulls), or 1 gen, 4 dull totems and an Exit Gate.

The most lucrative way to get points in Evader is pallet stuns, but those can be hard to land depending on the killer. Generally, as you say, it's very difficult to get Iridescent Evader unless you run the killer around successfully for basically the entire trial.

Also, I believe "Unbroken" is the name you're looking for for that final emblem 😊

Now what's your advice for getting these emblems, if you can only get matches against Survivors that are way better at the game than you, and you take forever to find a match playing as Survivor?

You must be better at being chased than me, then! I still haven't been able to crack the code on that darn Evader emblem, no matter how many times I read the wiki page.

That's more my playstyle as well, when I do get chased, but I tend to go for stealth if I can get away with it. Maybe that's why I have so much trouble with Evader, because it rewards doing well in chases. I wish stealth were a more viable strategy as far as the emblems are concerned.

Nope. Evader awards points for being in the terror radius, but they're pretty pitiful compared to the points you can earn in a chase and won't get you anywhere close to an Iridescent emblem.

Unbroken simply rewards you based on whether or not you escaped, and how well you did. Bronze for dying early, Silver for Dying late, Gold for survivor, Iridescent for surviving without getting downed.

And yes, Lightbringer and Benevolent are my bread and butter in this game as far as ranking goes.