The RPCS3 team has stated that porting their emulator to PS4 is "near impossible" due to the PS4’s 1.6GHz CPU bottleneck. PS3 emulation requires a 4GHz+ Intel CPU. Even the PS5 struggles with PS3 emulation (which is why Sony still uses cloud streaming for PS3 games on PS5).

Regarding safety concerns:

: Have the PS3 game in a format that can be used for conversion (typically a .pkg or .iso file).

If you want PS3 games on PS4:

Leo’s basement smelled of ozone and cheap energy drinks. Before him sat his PS4, "The Monolith," humming with the low, persistent fan-whir of a machine pushed to its limits. On the screen, a line of code flickered—a ghost from a previous era trying to find a home in a body it wasn't born for.