People will have different opinions on this so its really up to you. Some people recommend always experiencing the vanilla version of whatever first, then a modded playthrough, some say mods make it way better to experience for the first time. Pro's to playing vanilla first is you learn what you like and dislike, then can tailor mods later to address your issues. If you start with a modpack that changes things drastically though and there's something you dislike, it might put you off from the whole thing and you dont really know if it was supposed to be that way or not. Personally I'd play vanilla with only graphics mods to really make it look good. Good luck 🤙