Yes and no. with the bootrom keys you can't just start homebrew as if those keys are some sort of admin password.
With the keys you can see the code that runs when the PS5 starts up and at this point none of the security systems are up and running.
Once the security system is up and running, it is really hard to find a fault that can give you full/kernel access to the PS5.
The bootrom is a small chip with some encrypted code that gets loaded by the system and gets decrypted internally in the CPU.
So without the bootrom keys, you have no idea what the system is doing to start up.
The bootrom itself was already dumped a long time ago but without the keys, it is pretty useless.
But with the keys we can just read the code.
If you can find a bug in the bootrom, then that opens up a possibility to abuse that to run an exploit.
For example the Switch had a special mode where 1 pin would need to be grounded and it would read another bootrom from USB. That allowed hackers to load a patched bootrom that executed another exploit.
Chances that there is such a simple bug/feature in the bootrom are pretty slim these days.
Also, if you know the exact code that is run by the bootrom, you might be able to use something like voltage glitching and code injection to make the PS5 run code it wasn't supposed to run.
This is how the modchips on the Switch work. The modchip lowers the voltage, causing the CPU to skip an instruction and continue reading the next bootloader from the flash memory, that is replaced with some other code/exploit that gives full access to disable all piracy measures that Nintendo had put in place.
But the PS5 is a whole lot more complex so I suspect it will take a long time before we see any modchips on the PS5.
