It's been almost a year that I posted this guide and I wanted to do some updates to the guide (since you can't edit posts here after few days passed)
For macOS 10.13/10.14 users, run this terminal command instead:
Code:
open -a Steam --args -forcesteamupdate -forcepackagedownload -overridepackageurl https://web.archive.org/web/20240918104445if_/media.steampowered.com/client -exitsteam
As a side note, the client may sometimes corrupt itself after it finishes updating. You may also definitely need a newer Steam client (preferably through separate partition if you're not comfortable installing games through terminal) to handle modern game downloads, due to the introduction of ZSTD chunk compression.
And for those who are running macOS 10.15 or 11, despite several monthsafter the announcements, the latest version still works as of making of this post, although Valve will (presumably) update CEF 126 to 138 on the next major release, breaking 10.15 support completely. I will announce that breakage once there are updates made to it.