Ren's beginner-level [Life Skills] were troublesome since they would prevent him from crafting rare items and Artifact equipment.
He needed all his [Life Skills] related to Alchemy to be at the maximum [Grand Master] level to be able to craft legendary equipment and items.
This was another point that he needed to address. Actually, the very first point he needed to address in his Alchemic journey.
Ren listed on his side notes the things he needed to do. It also helped to organize his thoughts since he had trouble doing so with all the information in his brain.
First things first, he needed to upgrade all his [Life Skills] to [Grand Master] ASAP. The sooner he crafted artifacts, the better. He didn't have time to waste practicing his skills until it reached the [Grand Master] Level. That would take months in real-time!
His best bet was to kill High Gods and acquire there [God's Fruits] that could raise the [Life Skill] level to one.