You can

• Watch network access - What is communicating to the outside? Why is it? What is it communicating? I like sniffnet
• Watch CPU and GPU usage - What is using resources? Why is it? I like Mission Center and ps auxf in the terminal
• What is using the disk? I like Filelight and Disk Usage Analyzer
• Run AV software. I don’t have any recommendations.

You can also assume you are compromised and use a solution like a Faraday cage. If you’re trying to detect advanced spyware, it might be better to check network activity from outside the device like what network activity is the router managing for the computer.

The traffic seems well ranked still. Maybe concerns of algorithmic censorship? As an example, X.com now promotes posts from premium users, and then has an extra promotion mode for premium+ users. (Normal users are now much less visible than premium users)