ContraDix At this point, I'm a bit lost. Either you are over-thinking the problem or I am under-standing the problem.
If you are planning to install a "clean" installation of Solus (that is, allow the installer to wipe the SSD, repartition the SSD, and install Solus as the only operating system), the state of the existing OS (FreeBSD or whatever) and the existing partitioning on the SSD, whatever might be on the "InstallCD) and so on are irrelevant (unless the SSD is encrypted, which does not seem to be the case). The "clean" installation process overrides/replaces everything on the SSD.
I would like to clarify two basics before going further:
(1) Can you identify the make/model of the laptop? Usually this information is on a tag/label affixed to the computer. If there is no tag/label, check the box in which the computer arrived or perhaps an invoice to see if you can get the information. If you can identify the make/model of the laptop, what is the make/model? That information will help us identify the audio hardware in the computer, which might help us better understand the audio driver errors you reported in your original post.
(2) Can you identity the operating system currently installed on the computer? At one point, you suggested that FreeBSD was installed, but other things (e.g. the reference to InstallCD) suggest that the operating system is not installed at all. So a very basic question: What happens when you boot the laptop, without the Solus USB or anything else attached? Does it start an operating system (e.g. FreeBSD) or does it take you to a menu that allows you to install an operating system?
As @WetGeek discussed, the audio driver issues** might be related to the fact that the "Live USB" kernel is 5.13, which is about a year old and contains older drivers, rather than 5.15, which is more current and contains newer drivers, and that "[t]he point of all this is to eventually get you to a TTY, a character-based terminal, where you can enter a sudo eopkg up command to update your computer from the Solus repository". Although we might get enough information from the make/model, we might need to go a step further.
The errors you are reporting suggest that the sof-firmware package is not installed in the 5.13 kernel or not current.
70.759323] sof-audio-pci-intel-tgl 0000:00:1f.3: error: request firmware intel/sof/sof-adl.ri failed err: -2
70.759431] sof-audio-pci-intel-tgl 0000:00:1f.3: you may need to download the firmware from https://github.c...
70.759538] sof-audio-pci-intel-tgl 0000:00:1f.3: error: failed to load DSP firmware -2
70.760750] sof-audio-pci-intel-tgl 0000:00:1f.3: error: sof_probe_work failed err: -2