Distribution: Ubuntu 20.04
Hardware: MacBook Pro 15-inch (mid 2010) that was lying around.
The MacBook Pro “Core i5” 2.4 15-Inch (Mid-2010) is powered by a 32 nm, dual-core 2.4 GHz Intel “Core i5” I5-520M (Arrandale) processor, with dedicated 256k level 2 cache for each core and an 3 MB a level 3 cache. This system also supports “Turbo Boost” — which “automatically boosts the processor speed based on workload” up to 2.93 GHz for this model — and “Hyper Threading” — which allows the system to recognize four “virtual cores” or “threads.”
Best guide I found, works like a charm: https://www.wikihow.com/Install-Ubuntu-Linux#Preparing-to-Install
Best thing: I can also boost RAM from 4G to 8G. More about that later.
Worst thing: the CPU is not modern enough for most machine learning tasks (as shown here).