Sunlit Tides has too shallow of water for sims to drown in...well it'd be different if you went deep into the lagoon or open ocean but sims that are to be lifeguarded don't go anywhere near that far. When I tried it I got plenty of sims attending the beach but all they did was wade in the shallow water and waste my time.
The lifeguard at pool mod is awesome, especially because ST has multiple public pools already. You can also technically max the career by maxing athletic and charisma though you may need the Ambitious trait alongside it or the Entrepreneurial Mindset LTR.
