The problem with installing mac os El Capitan by internet
I've an old 24-inch intelmac, which is used by member of family just for internet etc. it's slow and someday then I'll buy new instead of main will be swapped (main is a bit newer intel imac from 2017, it's my third imac btw) this one with el capitan will be abandoned, but for at least few months this old one must be alive. Recently this worn-out colleague experiencing gray screen, system not starting, old DVD with installation of snow leopard is probably too old and stopped cooperating with dvd drive. I'm trying installer from Apple.com by the internet but it stopped working with 403 error, and info that access or installer is forbidden, it's pretty annoying that ever for this installer I've to be logged into icloud, it's kind of embarrassing. Installator from How to download and install macOS - Apple Support is useless because it's not compatible with my newest mac, I can't download it by appstore too. What with my right to repair? Guys, please be serious, business is business but sometimes people need have older macs alive, You have to respect the old customers because they will stop persuading new ones to buy Macs, it's one reason, but good one I think. Of course, I don't have to write anymore that there are bitter people who return to windows while remaining even more bitter, but they have no choice, because if there are no more decent computers anyway, it's better to buy cheaper ones.
I am writing this with the hope that there are some serious people here who are more experienced and will save me some time by suggesting a few helpful lines of code or something similar. I used to have an application to make such installations, but I don't think it's there anymore, the developer disappeared from the web, or I can't find it because this page dropped in the google ranking. Please help!