There are a lot more, but here is my recomendation:
1) Be the Actor (THIS ONE IS HELLA GOOD)
2) Once again an idol (this one is a go back in time but i needed to add it)
3) Saving the Doomed Idols With My Touch
4) Highschool Lunch Dad (kinda like, i died, but i want to be there for my daughter)
(Im lazy to find more, but i hope this helps )
https://www.mangago.zone/read-manga/i_became_the_youngest_top_idol/
https://www.mangago.zone/read-manga/acting_genius_top_idol/
https://www.mangago.zone/read-manga/the_maknae_has_to_be_an_idol/
https://www.mangago.zone/read-manga/a_tidal_wave_of_glory/
not idol/showbiz but also good
https://www.mangago.zone/read-manga/this_is_the_law/
https://www.mangago.zone/read-manga/again_my_life/
https://www.mangago.zone/read-manga/judge_lee_han_young/
https://www.mangago.zone/read-manga/real_man/
https://www.mangago.zone/read-manga/level_up_doctor_manhwa/
https://www.mangago.zone/read-manga/king_of_drama/
https://www.mangago.zone/read-manga/rescue_system/
https://www.mangago.zone/read-manga/the_heavenly_demon_will_give_you_a_massage/
You guys got any manhwa’s where they reincarnate into the modern world: kinda like debut or die