"malfunctioning phone-as-a-key functionality, a useless keyfob, a keycard that rarely worked quickly, constant phone connection issues, infotainment glitches and error messages"
is not needing the same functionality that the following provides:
"a Nvidia Drive AGX Orin-based core computer that has contains over 500 TOPS (Trillion Operations Per Second) of power, which Volvo says will help power its autonomous driving ambitions"
This is for lane assist, speed limit assist, auto-braking, follow mode, and other modern cruise control systems that many don't use.
This really should not be same computer (but I presume there is a VM here with static allocation) as the keyfobs, bluetooth, and especially the infotainment system.
I suspect the wireless module in the old computer board was crap (or otherwise poor motherboard design) and the new board fixes that, but also comes with the above features as a bonus.