It is hard to associate in the same sentence the word "powerful" with a quadruple Cortex-A53 CPU.
Cortex-A78 is in a totally different class of "powerful", when compared with Cortex-A53. Cortex-A53 has not been designed as a top performer among Arm CPUs, but only as a low-power core. Even at its launch, in 2012, 14 years ago, Cortex-A53 was much slower than the older big Arm cores, like Cortex-A15 from 2010. I am aware of this from direct experience, because a decade ago I have developed software on several SBCs with Cortex-A53, including Raspberry Pi, and also on an ODROID model with Cortex-A15, which ran circles around them, and unlike them it delivered a passable desktop experience.
On the other hand, at its launch in 2020, Cortex-A78 was faster than any older Arm CPU cores. It was then surpassed by the Cortex-X1 launched simultaneously with it, and then by the Apple M1, launched later that year.
Even if some enthusiasts have used old Raspberry Pi and similar SBCs with Cortex-A53 as PCs, that was really not wise as they were too slow for a comfortable use and there were faster alternatives with a similar price (after you added the cost of all required peripherals).