Mixed-level parties are more common in organized play than home games and can be more dangerous for low-level characters in Pathfinder 2e due to the 3 action economy and +10 to crit. In Starfinder, mixed-level parties can work well as long as difficulty is adjusted and low-level characters are given opportunities to contribute. To make them work better, consider using tiers, awarding bonus experience to low-level characters, and designing encounters that challenge the whole party.
