Two engines better than one for sure. One engine in tip top shape better than two with deferred maintenance. Plenty of commercial boats with one engine. Some issues like fuel will impact both engines. Having all the safety gear and backups mitigates risk. Smart captain most of all.
Being able to troubleshoot/repair and have spares is critical for me.
I’d also say that having at least one passengers being pretty salty is big.
In my 208/200hp/hardtop for now I go about 15-20 miles from Barnegat Inlet max since I don’t have some of the backups. Need a second bilge pump or a backup emergency pump, backup nav and vhf, EPIRB in addition to PLB, would like radar and a raft. Next year I think I would be good for 50-60 miles with those additions. 85-90 miles to Tom’s Canyon, that is stretching even with forecast good weather. Comfort level, long way for an assist or tow, long slog home if the weather turns upside down, fuel (208 tank is 84 gallons, would want to have 20g more).