Kaylan is surely most developed/most realistic character here including she is beautiful but not over-beautiful. Totally wife material.
Valentina is surely all-in-one package, it's Hard to not make her MC's queen... but it surely breaks balance in last chapters, she Just gives too much profit as a choise.
Other sisters... middle one is too stupid, oldest is good choise if you wanna give up all decisions and let her rule (not too long, surely it Will end with MC and all royal family lose their heads)
"Goddess favourite" is not the worst choise tbh, she knows what she wants, smart, good at politics, and it seems poisoning MC is not in her Best interest.
Viking Princess is also good variant, at least I think MC Will rule safe and long enough with such woman close to him.
I do like that annoying little blond "from past" , Just very bright character with fun interactions, and that stupid little slut loves MC almost like Val
Flora - Will be most loyal bodyguard and concubine for sure
Edit: almost forgot, Queen, yeah... let her fuckin' rest, take her son and go living somewhere far far away and enjoy their lives, forcefully if needed.