The short answer is: almost certainly not. The e-fuse system is a hardware lock that has never been defeated on any modern console (PS4, PS5, Xbox One, Series X). The PS3 allowed downgrading because it lacked e-fuses. The PS4 does not.
Creative hackers have found ways to emulate lower firmwares or trick the kernel temporarily, but a permanent downgrade that survives a reboot is not possible without physically replacing the motherboard’s security processor (Syscon). That is far beyond typical user capability. ps4 downgrade tool
What you might see in the future:
Until then, treat any "PS4 downgrade tool" as a myth. The short answer is: almost certainly not
You will find people offering a "remote downgrade service" or "send your PS4 to us and we downgrade it for $150." Be extremely skeptical. Many are simply reflashing your NOR chip (risky) or swapping your motherboard with one from a lower-firmware console (which is essentially buying a different console). Some are outright thieves who keep your console. Only use well-reviewed, community-trusted repair shops. Until then, treat any "PS4 downgrade tool" as a myth
Every PS4 game disc contains a minimum firmware requirement embedded in its PARAM.SFO file. If your system is below that version, the disc won’t boot. Similarly, the console’s bootloader is designed to reject any firmware attempt that is lower than the highest efuse value recorded.