In my job usually sell computers with VERY cheap ass power supply that in some cases exploded on the first power on lol.
Overvoltage can kill the hardware. I see some cheap ass PSU with 14.0V on the 12V+ killing a motherboard in 1s and in some cases also damage the CPU and RAM. Undervoltage usually after sometime melt connectors because increase the current, but I never see dead hardware for this problem, just the CPU power connector melted, replace the connector and the motherboard work just fine.
Ripple is also very bad for the components, specially capacitors. I see some PSU with severe ripple making pop corn of a motherboard
I7 8700K@4.7Ghz / Z370-A / 2X8GB 3200Mhz ADATA Spectrix D40 / 1TB Intel 600P / EVO 850 250GB / 4TB WD Gold / RTX 2080 GAMING OC / NZXT Noctis 450 ROG / EVGA G2 850W@ECO
Heatkiller REV 3.0 / XSPC EX360 / DDC 3.25 + EK-XRES / 3x Venturi HF-12 PWM