I remember reading and liking both the Sister Joan series by Veronica Black (pen name for Maureen Peters) and the Dorothy Martin series by Jeanne M Dams, back in DTB days. Now there are omnibuses of several books in each series on sale for $0.99/£0.99.
The Dorothy Martin Murder Mystery Box Set, Books 1-5 contains:
The Body in the Transept (which won the 1995 Agatha for Best First Novel),
Trouble in the Town Hall,
Holy Terror in the Hebrides,
Malice in Miniature, and
The Victim in Victoria Station
Kindle US:
https://www.amazon.com/dp/B09XBD1LG4
Kindle US/Smile:
https://smile.amazon.com/dp/B09XBD1LG4
Kindle UK:
https://www.amazon.co.uk/dp/B09XBD1LG4
Kindle UK/Smile:
https://smile.amazon.co.uk/dp/B09XBD1LG4
The Sister Joan Mysteries, Books 1-5 contains:
A Vow of Silence,
A Vow of Chastity,
A Vow of Sanctity,
A Vow of Obedience, and
A Vow of Penance
Kindle US:
https://www.amazon.com/dp/B09842ZY2H
Kindle US/Smile:
https://smile.amazon.com/dp/B09842ZY2H
Kindle UK:
https://www.amazon.co.uk/dp/B09842ZY2H
Kindle UK/Smile:
https://smile.amazon.co.uk/dp/B09842ZY2H