You can’t go wrong with a Glock 17, 47, or 19 from a reliability, simplicity, or aftermarket support standpoint. They are also very modestly priced for what you are getting. I will buck the general consensus here and advise you to stay away from any of Sig’s striker fired pistols (P320, P365). I’ve personally seen and experienced too many issues to recommend them. I’ve also had a poor experience with their customer support the only time I’ve used it. Plus mags for them are outrageously expensive.