I think, anecdotally, there may be a possibility of more temperament issues with solids than with roans/ particolours. That's not to say that there aren't plenty of lovely, temperamentally sound solids out there and conversely roans & particolours with issues, but I personally, from what I've read more generally and heard described by others tend to think solids present more often with issues like guarding. (Owner of black solid male with quite advanced guarding issues).
Probably more important than any of that is that you make contact with breeders who you feel confident in, can reassure you that they have dogs & had litters with no known serious temperament issues, and that ideally, you can see and interact with both parents who both appear well adjusted and free from any nervous behaviours.