Maintenance on my iMac

The best way is to leave it alone and NEVER install antivirus, cleaning or ANY other third party "maintenance" apps. If simply kept up-to-date and otherwise left alone Mac OS will remain fast and stable for years.

Don't install "junk" such as antivirus, cleaning or maintenance apps.

Keep macOS up to date, backup using Time Machine and enjoy.

Macs maintain themselves. Maintenance scripts are run automatically from within the system in the background. Don't even think about using any third party so-called "cleaning" apps.