HELP: Mac user on 10.14.6; failed update to Catalina+, now downloads are breaking as of early July
As the title says I'm on a recently outdated version of Mac and can't seem to get my hardware updated past 10.14.6 :( The client and all my games have been working fine until early July, when certain downloads started breaking.

For the affected downloads, (which seems to be any update from after July 5/6th) the download starts, gets part of the way through, then stops, either never completing (staying at 0 kb/s forever) or halts completely, giving one of three different error messages: "content unavailable", "content servers unreachable", or "corrupt download".

Sometimes, workarounds help, but not always. Sometimes, after the download stalls out, I can download something else, then restart Steam after it finishes. When I re-open Steam, the update triggers automatically and installs properly. WACK.

I understand I don't have technical support from the Steam team, so I'm hoping one of you wizards here can either help me with a workaround to get my OS upgraded, or find a consistent workaround for these downloads.