Memo for myself, if I need to make this again in the future…
On the first computer, I set the sync directory to iCloud. First, create a new directory on iCloud, then move my Sublime Text 3 settings and preferences into it, and then link this local destination to my iCloud folder.
UPDATE – for Sublime Text 4
For Sublime Text version 4 skip the number in the path.
# make new directory on iCloud
mkdir ~/Library/Mobile\ Documents/com~apple~CloudDocs/Sync/Sublime\ Text\
# get in application preferences folder
cd ~/Library/Application\ Support/Sublime\ Text\ 3/
# for Sublime Text 4 without a number
cd ~/Library/Application\ Support/Sublime\ Text/
# move User data for syncing do iCloud
mv Installed\ Packages/User/ ~/Library/Mobile\ Documents/com~apple~CloudDocs/Sync/Sublime\ Text\
# link this directory on iCloud to the app directory
ln -s ~/Library/Mobile\ Documents/com~apple~CloudDocs/Sync/Sublime\ Text/User
On my other computers, I used these commands. Go into the Sublime Text Packages directory, remove the old User directory and then link it to synced folder.
# get in application preferences folder
cd ~/Library/Application\ Support/Sublime\ Text\ 3/Packages/
# for Sublime Text 4 without a number
cd ~/Library/Application\ Support/Sublime\ Text/Packages/
# remove folder User
rm -r User
# link to User folder on iCloud
ln -s ~/Library/Mobile\ Documents/com~apple~CloudDocs/Sync/Sublime\ Text/User