

In fact, in the EU that is regulated by article 6A (see https://eur-lex.europa.eu/legal-content/EN/TXT/HTML/?uri=CELEX%3A52021XC1229(06) ) . That states amongst other things that:
Any announcement of a price reduction shall indicate the prior price applied by the trader for a determined period of time prior to the application of the price reduction. … The prior price means the lowest price applied by the trader during a period of time not shorter than 30 days prior to the application of the price reduction.
So maybe it wouldn’t apply for a 3 month period, but it does prevent stores from increasing the price by say 20% overnight and then give a “10% discount” the next day.

Have a look at DietPi. That is a single-board-computer optimized Linux distribution that, in contradiction to what the name might suggest, runs on (almost) all of the SBC’s out there. It has stripped away all the things you don’t need and only installs and loads what is needed to run the software you choose, resulting in a very lightweight but powerful operating system for these kinds of devices. It has its own software catalog with a broad selection of optimized software, but you can of course install anything you want. Ive been running this on a Raxda Rock4 without any problems, and would definitely suggest this even on a Raspberry over the regular Pi image.