I am sorry to hear of your difficulties with the S20FE, and the suspected hacking. If you’re worried about your phone getting hacked, or if you think it may have been hacked already, there are some steps you can take to keep it safe. For example, you should only download apps using the Galaxy Store or Play Store and you shouldn’t click on malicious links in apps, texts, or emails. You can also keep your phone safe by running anti-malware apps and removing apps that are causing issues. Try these steps: https://www.samsung.com/us/support/troubleshooting/TSG01209886/
Please let me know if this helps. Thank you in advance.