DeletedUser313 Cellebrite likely to be available on every police station's main work-laptop?
Forensic tools are not deployed on work PCs. For best practices and to ensure forensic soundness, they'd use kiosk PCs made for the purpose of being used in a digital forensics lab. Some OEMs sell PCs with forensic utilities and hardware such as write-blockers, drive bays, or GPU racks (for intensive tasks like brute forcing) built in.
If talking only about Cellebrite the products is usually deployed in two ways:
On PCs for use in kiosks or laptops by the customer. This would be installed with a variant of UFED called UFED 4PC. If you want to use Inseyets, their flagship solution, you would need a kiosk. They don't support their tablets yet.
A portable device, such as a tablet PC that runs the UFED software. Example of this is the UFED Touch series. The tablet only runs UFED, so it would just perform extractions that would be sent to an external storage device or to a target kiosk PC by connecting to it via a cable.
A bonus third option is Cellebrite Advanced Services, where a client can mail the device to Cellebrite and have them perform the forensics for you. This would be useful in complex cases or if a supported device is flagged as only being available in CAS.
You would typically order the tools with a big case of necessary hardware (cables for phones and countless connectors for legacy phones, manuals, carry cases, dongles, DRM hardware).
Every tool however may deploy it differently, for example, GrayKey is known to depend on a hardware device and they used to NDA people to not discuss it's appearance and customers instructed not to let authorised people in the same rooms as the device. Everyone sort of knows how the products look now though.
As for immediate access to the tools, it depends on funding, headcount and societal factors. A police headquarters in a modern European country would likely always have a kiosk, even at a low level, while a rural police station in America might not have that. Some may also not have licenses for the top class like Cellebrite Premium, which means a device meeting a description of something they can't work with would be escalated/transferred.
Some countries operate labs in different levels and sizes and may move a device to a more advanced, dedicated laboratory if they aren't able to get access or have the tooling. Some less wealthy countries may not even operate in a lab and have little or no oversight or care in forensics processes, or even downright use the tools maliciously.
An example of high level forensics labs are the FBI's RCFL (Regional Computer Forensics Laboratories), each lab covers a large area and you would expect difficult cases or serious crimes to escalate up to them.
https://www.rcfl.gov/about
You'll see forensics tools not just deployed by citizen facing law enforcement or police, you may see it in other security agencies like DHS, or the Secret Service. The latter operates a huge forensics facility called the National Computer Forensics Institute. A government department investigating financial crime or cyber security would too.
DeletedUser313 would a forensic investigator be able to do a full filesystem extraction in BFU (say Pixel 9 GOS latest) to check if it was truly voluntary? Meaning would one have to wipe their Pixel 9 before they depart?
Not without knowing the device password AND any profiles' credentials. They would need to exploit the secure element to even have a chance of brute forcing it, but if the password has a high enough entropy that it can't be brute forced regardless, there's no chance at all.
This isn't accounting for additional settings like USB port controls as well. That would disrupt things further.