This singer is involved with the doujin circle priere*, and the unit *baletta.
BOOTH page for priere*:
https://kisskz.booth.pm/
Twitter for *baletta: @baletta_info
By the way, the reading for the Kanji in her name came from OnoP when I asked him on Twitter.
Source:
https://twitter.com/onop8424/status/1231575874140377088