What would happen if Japan made the bold decision to allow female-line succession?

Part 1: https://mlbpark.donga.com/mp/b.php?p=1&b=bullpen&id=202609100118617636&select=&query=&shop=&subselect=&subquery=&user=&site=&reply=&source=&pos=&sig=hgjTGgtgj3aRKfX2hda9Rg-ghhlq
Part 2: https://mlbpark.donga.com/mp/b.php?p=1&b=bullpen&id=202609100118619820&select=&query=&shop=&subselect=&subquery=&user=&site=&reply=&source=&pos=&sig=hgjTGgtgh3DRKfX2hda9Rg-ghhlq
Part 3: https://mlbpark.donga.com/mp/b.php?p=1&b=bullpen&id=202609130118666326&select=&query=&shop=&subselect=&subquery=&user=&site=&reply=&source=&pos=&sig=hgjTGgtgg3eRKfX2hda9Rg-ghhlq
Part 4: https://mlbpark.donga.com/mp/b.php?p=1&b=bullpen&id=202609130118666815&select=&query=&shop=&subselect=&subquery=&user=&site=&reply=&source=&pos=&sig=hgjTGgtg63aRKfX2hda9Rg-ghhlq
Part 5: https://mlbpark.donga.com/mp/b.php?p=1&b=bullpen&id=202609130118666905&select=&query=&shop=&subselect=&subquery=&user=&site=&reply=&source=&pos=&sig=hgjTGf-Yk3aRKfX2hda9Rg-ghhlq
If limited to the current male-line succession, the order of families closest to the current Imperial Family is as follows: Descendants of Takatsukasa Tsukehira, the 4th son of Kaninomiya Naohito (famous descendant Saionji Kinmochi; the main line is 21st cousins with Hisahito & Aiko) - Descendants of Konoe Nobuhiro, the 4th son of Emperor Go-Yozei (famous descendants Konoe Fumimaro & Hidemaro brothers; the main line is 29th cousins with Hisahito & Aiko) - Descendants of Ichijo Akiyoshi, the 9th son of Emperor Go-Yozei - Descendants of Sadatsune, the second son of Fushimi-no-miya Sadahusa (adoption candidates are 40th cousins with Hisahito & Aiko).
The descendants of the first three families are more than 10 degrees of kinship closer than the families that have recently become eligible for adoption, but they are ultimately strangers beyond the 20th degree, and crucially, they are people who have moved to other families, so they are not eligible for adoption.
Even if they try to follow public opinion and switch to female-line succession like Europe by giving succession rights to princesses instead of giving them to people beyond the 20th degree, there are problems. More princesses than expected are childless. The current princesses among Akihito's descendants are as follows:
Aiko (25), Mako (35, 4th cousin), Kako (32, 4th cousin), Sayako (57, aunt).
Aiko is still in her 20s, Mako's marriage process was a mess so public opinion is more hostile toward her than Hisahito, Mako's younger sister Kako is still unmarried, and Sayako married too late and has no children.
In the Japanese political sphere, which has modified the law to allow the adoption of 40th cousins while shouting about the "unbroken imperial line," allowing female-line succession would be equivalent to saying the Fushimi-no-miya family has completely hit rock bottom, so Mako and Kako would naturally be automatically excluded.
If female-line succession is recognized, the next in line after Aiko would be the descendants of Shigeko, the eldest daughter of Hirohito. Shigeko's husband is Higashikuni Morihito, and her father-in-law is the Higashikuni Naruhiko mentioned in the previous post.
Ultimately, the only difference left is whether the former imperial families enter as adoptees with a pure male-line 40th-degree kinship, or whether some descendants of Higashikuni Naruhiko enter as 7th cousins to Aiko.
It is said that the former imperial families, seemingly aware of their own plummeting public reputation, prefer to "ride the bus" as Aiko's husbands rather than becoming adoptees with 40th-degree kinship.