They do have an official save converter[1]. Not sure if it works with the latest versions of CKII and EU4 but it's definitely worked in the past.
Hell, you used to be able to do the "Grand Campaign" where you play CKII->EU4->Vicky->HOI to cover about a millennium of history. Once again though, not sure if the save file converters have been updated enough to do that now.
Hell, you used to be able to do the "Grand Campaign" where you play CKII->EU4->Vicky->HOI to cover about a millennium of history. Once again though, not sure if the save file converters have been updated enough to do that now.
[1]:https://ck2.paradoxwikis.com/Europa_Universalis_4_Save_Conve...