[Yareli] has become a Diamond, and as such, is now UNBREAKABLE!
This build is certainly not cheap (it does require 2 Umbra Forma, after all!) but it is literally unkillable with a little help from 5 Azure (Blue) Archon shards all equipped with 5HP/s for a total of 25HP/s!
Fun Fact: Merulina ALSO benefits from the HP [Regen] of the Azure Archon Shards!
Be sure to use a VERY nice secondary weapon with any Yareli build. If you aren't riding Merulina, you're doing it wrong.
If you're looking for a good easy-to-use weapon build, check out my "Apeiros Prime" link: https://overframe.gg/build/387318/tenet-cycron/apeiros-prime/
Now obviously you don't need to use the exact same setup, you can replace all of the duration mods with more health/armor or strength mods (or whatever else floats your K-drive), but I personally still want to use Aquablades, just for the fun factor, that's why I have the duration mods. If you just want to go full-on strength, then go for it! But I would definitely recommend keeping all three Umbral mods.
I have tested this in Steel Path and I can literally just sit still and let them fire upon me to almost no end. It truly is something else!
Note: there is currently a glitched, broken, or intentionally dumb system that lets Sentient lasers knock [Yareli] off of Merulina.