I’d read through the above, and iterate the search for more cases to get a better oversight on what people are doing. Some of the comments point to it being difficult to associate a new wallet, but other seem to indicate that they managed to through support. Plenty of comments stating that they should have bought a hardware wallet.
The important thing would be to try to sus out the door in your security that allowed this to happen. I’d consider your environment compromised, and would not currently trust anything in your environment. You may have downloaded some software, even different to the one you mentioned, from a malicious installation, that could have piggybacked any kind of keylogger or else during its deployment (see for example https://bitcointalk.org/index.php?topic=5375639.0 on how malware can piggyback around).