I think he trained hard to be here. The problem is the strategy when you have such long break. His BH to BH is still great but how many down the line shots he made I think 0, look how many mistakes on short game ad also problems with reading serves. This is what you loose when you have long break.
Actually, I thought ZJK's service and receive were decent. Most of his receives are short and prevented Yoshimura from having a 3rd ball kill shot. On the other hand, Yoshimura had more trouble with ZJK's serves. Yoshimura lost many points just from service receive and ZJK was able to perform many 3rd ball attacks with BH. Overall, ZJK lost far fewer points from service and receives than Yoshimura, so I don't think that's the most critical failing.
ZJK also attempted to go down the line with his BH in game 2. But he miss on both occasions, so he gave up on that. I think after a long break, he's rusty on down the line shots, which is understandable.
I think ZJK's main problem is footwork and FH. He is still too slow to keep up with Yoshimura on longer rallies. His forehand is also weak. Although Yoshimura has a very strong FH, ZJK needs to be able to consistently beat him on FH topspin rallies. But that's not the case. ZJK won only 2 FH topspin rallies throughout the entire match. Many of this FH 3rd ball attacks are driven back by Yoshimura.
Overall, I think ZJK executed the correct strategy. He exploited Yoshimura's weaker BH. I noticed most ZJK's points are earned through BH rallies. He practically glued Yoshimura to the BH side of the table, so Yoshimura can't use his powerful FH as much.