Turns out the older your data the less it is worth
That’s why I think is not the best approach to delete your accounts. Keep an old phone with all your accounts and every now and then watch a random video, make a random search, follow a random profile, and so on with all your accounts. Over time your true profile will become obsolete and buried under fake data.
Yeah, the solution to apps selling your data is using only free software, the only problem that still remains is that your mobile network provider also sells your location data.
Social Media is not the only problem, it’s far worse than that and you will not solve it leaving social media. Your employers get all the information about you from what is called ‘data brokers’ which are the ones who buy the data collected by all the apps that you install in your phone and sell it to everyone interested, not only companies trying to sell you something, but also employers like the case you posted and also state agencies, who dodge in this way breaking the law by spying you. That’s the big business of data collection. Here an investigation made by german journalists How data brokers sell our location data
We are talking about privacy, not security, like when being individually targeted by the state or someone else, that’s another topic. Privacy-wise the main source of information about you comes from apps that collect all the information available (which is huge), they sell it to data brokers which in turn sell it other companies that tipically try to sell you something or want to know your habits (like your employers). If you don’t use their apps they can’t collect information about you and sell it, and that happens when you migrate to free software. Only location will still be collected because mobile service providers log it and sell it, but there are ways to mitigate that too.