Thanks for your reply. Yes, the sense of my message was to get some Japanese websites to find information. However you're right, I find it strange because I'm probably too used to our Western culture, where the private life is quite tied to the public one.
Anyway, the actresses I was referring to (yep, I could have written them before, sorry) were and Michiru Sakura (桜みちる) and Yui Azusa (梓ユイ). They didn't actually perform in lots of movies, but I remember them with a kind of affection because they were the first JAV movies I watched in 2010/2011 when I still was a young university student and they basically "introduced" me to the JAV world.
UPDATE
About Yui, after some searching with Japanese keywords I was actually able to find some information that I share, in case someone is interested.
This article from 2020
https://www.fuzoku-move.net/special/azusa-yui.html retraces her entire history in the JAV industry from her debut. It states that she's never officially announced her retirement but she gradually disappeared from the scene from 2011, when she made her last solo-movie. Then, she only appeared in some collection-movies and her last appearance was in 2013. Now, it's supposed she's living a "normal" private life, since there is no evidence of her working in the adult industry in general (for example in a club). The reasons why she decided to interrupt her career were multiple (in brief: less popularity than expected, the contract renewal conditions were not good, she got enough savings and her movies were exposed to her relatives). It's also said that she continued to do something after 2013 and was active as a "planning actress" (企画女優, what does it mean?), but I don't understand very well the translation of those parts and my Japanese knowledge is zero (if someone knows Japanese maybe could help).
Moreover, she also had a blog at the time of her debut that she stopped updating in late 2010, where she shared a little bit of her private life:
https://plaza.rakuten.co.jp/yuiazusa. She hasn't any SNS beside this blog, apparently.