Adjacent protectors have a history of compromising (bypassing) protection already inside that PSU. A completely different solution (also called a surge protector) connects destructive transients to earth BEFORE it can enter.
If your PSU needs protection, then so does all other household appliances. Informed consumers earth a 'whole house' protector. Even a power strip or UPS protector needs that protection.
Effective protectors make direct lightning strikes irrelevant. Lightning may be 20,000 amps. So a minimal 'whole house' protector is 50,000 amps. This will cost about $1 per protected appliance. How much was that lesser power strip or UPS protector?
Protectors do not do protection. Protection is provided by what harmlessly absorbs hundreds of thousandis of joules. A 'whole house' solution is effective when connected low impedance (ie 'less than 10 feet') to an upgraded earth ground: single point earth ground. Most important component in any protection system (to even protect that PSU) is what any effective protector connects to - single point earth ground. That (and not a protector) is the 'art' of protection.