Japanese stocks: foreigner buying and the market; is the current market cheap in terms of supply and demand?

In the supply and demand that determine the Japanese stock market, the main players are active investors, namely foreign investors. Other factors include the Bank of Japan's ETF purchases and GPIF's changes to its basic portfolio. (Previous articleReference)
BOJ’s ETF purchases are nearly finished. GPIF’s basic portfolio changes have not occurred since 2015.
So, for now, overseas investor trends are the most watched, but...?

First, look at the weekly net buying by overseas investors plus BOJ ETF and the weekly change in TOPIX.
The two are almost in sync. However, since the start of this year, stock price movements have become more volatile. The reason is unknown. Has the cushion of BOJ ETF purchases grown thinner?

Next, from the perspective of three-month (13-week) monitoring by institutional investors,