Unless somebody makes a license generator in the style of Riglol, so you can install updates and use latest firmwares, I don't consider hacked Keysight a good thing.
Whole idea is that Keysight is more expensive despite being slightly inferior hardware and capabilities is that it is supposed to have superb quality of support. Which you give up voluntarily if you hack it.
You cannot install newest versions of firmware (with bug fixes) because of hack, and have to wait for months for new hack for new firmware. Not to mention if you have to send it in for warranty, and you have defect that won't let you restore factory firmware. And you have no clue what's gonna happen.
Don't get me wrong, new Rigols are also in that boat, but they don't carry price premium for services you give up on....