Self-hosting

some of the more aggressive antivirus software will flag anything related to piracy.

If you are certain it was the official lidarr and is safe, you can add it to a whitelist so it is ignored.

Wonderful day!

Depending on the anti-malware, it may be either a known signature, or heuristics.
- In case of the former, the signature may be a just a single use of function inside the safe program that matches with a malware that uses the same (e.g., in a thread or memory range the anti-malware probed);
- Heuristics - May just be too restrictive local security settings;

Yet, if you don't have enough time to investigate it locally in isolated environments as virtual machines/containers, debugging syscalls and activities in file-system, memory, network etc., there are less manual or outsources, options, including the common know ones:
- https://opentip.kaspersky.com/
- https://opentip.kaspersky.com/requests
- https://www.virustotal.com/gui/
- https://any.run/

Please stay safe!

See if the developers publish hashes of their executables (something like sha1/256, md5...). Then you can take the hash of your executable, and if they are the same, you should have gotten the exact same file. This does of course not help if the place you get the hashes from is also compromised.