The old method of installing Jenkins is not deprecated in favour of a Homebrew installation.
Install Homebrew as per this arcticle https://markjesson.co.uk/2020/02/27/installing-homebrew-on-macos/
Start by running:
brew install jenkins-lts
You should see output similar to the following: –
==> Downloading http://mirrors.jenkins.io/war-stable/2.204.2/jenkins.war
==> Downloading from http://mirror.serverion.com/jenkins/war-stable/2.204.2/jenk
######################################################################## 100.0%
==> jar xvf jenkins.war
==> Caveats
Note: When using launchctl the port will be 8080.
To have launchd start jenkins-lts now and restart at login:
brew services start jenkins-lts
Or, if you don't want/need a background service you can just run:
jenkins-lts
==> Summary
🍺 /usr/local/Cellar/jenkins-lts/2.204.2: 7 files, 63.9MB, built in 37 seconds
Start Jenkins using the following command: –
brew services start jenkins-lts
Jenkins will now be available on: http://localhost:8080. Follow the customisation prompts to complete the installation.

You can restart by running:
brew services restart jenkins-lts
Or update by running:
brew upgradejenkins-lts
Useful links: