Hmmm. If just similar Regression/ Time Rewind with European Ambience
Regression Time Rewind BL List
https://www.mangago.zone/home/mangalist/2774099/
#10 Regression, European Ambience
https://www.mangago.zone/read-manga/the_fallen_duke_the_knight_who_hated_him/
#21 Regression, European Ambience
https://www.mangago.zone/read-manga/how_to_raise_a_victim/
#29 Regression, European Ambience and Omegaverse
https://www.mangago.zone/read-manga/beta_count_so_has_changed/
#30 Regression, European Ambience
https://www.mangago.zone/read-manga/the_prince_and_his_mischievous_one/
As for Royalty Nobility/Aristocracy
Royalty Nobility Completed BL
https://www.mangago.zone/home/mangalist/2744390/
#2 European Ambience, Omegaverse
https://www.mangago.zone/read-manga/smyrna_capri/
#6 Eastern Historical, Regression, Royalty
https://www.mangago.zone/read-manga/you_own_my_all/
#9 Royalty, European Ambience
https://www.mangago.zone/read-manga/dragon_s_first_crush/
Royalty Nobility Ongoing BL
https://www.mangago.zone/home/mangalist/2763983/
#4 Nobility x Commoner
https://www.mangago.zone/read-manga/the_moon_painting_alchemist/
#7 Omegaverse, European Ambience
https://www.mangago.zone/read-manga/the_rogue_prince_is_secretly_an_omega/
#8 Isekai, European Ambience
https://www.mangago.zone/read-manga/to_deny_the_route/
You can check the lists lol. There's a few that's good
Any recommendations similar to Turning (yaoi)?
https://www.mangago.zone/read-manga/turning/