I would encourage to install every advertised VPN app around, every add-in security app, every add-on cleaner app, all of it, install it all.
That will ensure your metadata is properly collected and uploaded for advertisers and targeting, that you are properly exposed to added security exploits targeting vulnerabilities in the add-on apps, and that your Mac is unstable and flaky and slow.
You can then stop back here once it’s all installed, and ask for help with a Mac that is now running poorly.
Or, well, you can skip all that, and use the existing end-to-end connection security, and iCloud+ Private Relay and ODoH for privacy.