I think someone is spying on me, what do I do?

I took my MacBook in to get fixed, and since then I have noticed some odd behavior on my laptop. I have seen things like my screen randomly jumping to a different screen I have open, other times I will suddenly see a box pop up on my screen that says “Press Fn to exit full screen” but if I press Fn it doesn’t do anything… and the other day when I went to put my password in to log into my laptop I saw an orange light on that was located in the top right corner of my screen. Then I noticed a message on the top utility bar that said “your screen is being observed”. For that particular instance, I turned my computer off and on again before logging in, made sure I didn’t see that stuff anymore before logging in. Anyway, I have been suspecting someone spying on me for a while now but that time made me really think it. So I have been investigating a bit and came across something called “Thunderbolt” that is on my laptop so I did some Googling about it and it says it is used for moving files and sharing stuff. There are a bunch of these on my laptop, 2 of them say “Thunderbolt Bridge” but the rest say “1, 2, 3, 4… 8”. I could think that the ones that say “bridge” go to my Adobe product suite but am not sure about the rest. I saw on a thread that someone could spy on you using Thunderbolt but they would have had access to the physical laptop… and I did notice my laptop acting this way after taking it in to be worked on, so, I am feeling nervous that I am being spied on.

If anyone here has used Thunderbolt, could you give me some clarity as to what this could be about?

how do I know for sure someone did this and is spying on my laptop?

what should I do once I confirm that I am being spied on? Should I call the cops?