All three are indispensable.
Any defect or weakness in any part of the three main components would result in the inability to increase overall strength.
He had seen significant improvement in his physical constitution, and his comprehension of Taoist Intent had also improved. After all, he'd been running around for the sake of Taoist Intent and Demon Talisman Seeds lately.
Only the path of Formation Talismans had seen no substantial improvement for such a long time.
"The biggest trouble with Fourth Grade Formation Talismans is that they require the consumption of spiritual will during their creation."
This was an unavoidable aspect for him. The process of creating lower-grade Formation Talismans also expended spiritual power. However, he used to rely on muscle memory; if he succeeded once, his body could instinctively remember that trajectory and replicate it perfectly.