So here is the build in action on Hard fighting the Shroud
https://www.youtube.com/watch?v=A4G_2Kz9Foo

So, you can die, you can regen a lot, you can move pretty fast, you have tentacles that will heal you and you can also eat Plums sold by the Stuck merchant in Yaesha wich increase your hp regen for 1 hour.
It's a very complex build that needs a lot of stuff that's upgraded, some items if they are not upgraded they will perform worse.
To get all these things in a faster way you can use the save file reader wich shows what you have in your game, a bit exploitive but the Adventure mode will be out pretty soon so it's ok to get what you are lacking:
https://hzla.github.io/Remnant-World-Analyzer/

#1 Twisted armor , Random Earth Encounter, The Root Shrine, just survive
https://www.youtube.com/watch?v=YNh5emN6_IY

#2 The Ruin rifle upgraded so when you die you ressurect immediatly with 100% health and 10% damage reduction for a few seconds. Just kill the Undying King, he is not so hard to kill
https://www.youtube.com/watch?v=l4_0EHS6xIY

#3 Curse of the jungle god pistol, again upgrade it for a lot more damage, when the tentacles hit they actually heal you if you have the Leech Ember
Just kill the Ravager, it's his normal drop
https://www.youtube.com/watch?v=WypdJP1e3B4&t=115s

#4 Rive scyte, melee weapon that heals you when you damage enemies. Give the guardian heart to the Undying King( yeah you have to do the undying king 2 times) and he will reward you with it
https://www.youtube.com/watch?v=TpHhpGBRmnw

#5 Leech Ember , random ring found in Rhom, melee attacks regenerate hp, it shows in the world analyzer

#6 Blood Font, hp regen ring found in Corsus, use world analyzer

#7 Mender's Charm , increases hp regen, sold by Wud, Rhom merchant, pretty easy to get

You can also use a lot of traits to make it better like the Triage Trait from the shrine of the immortal wich is a siege that should always appear in Yaesha. The rest of the traits depend on you.