Every time I start RPH it installs a Trojan virus on my computer. Thanks to Windows Defender, these viruses are quarantined and can be eliminated without problems. But now my RPH won't start GTA V, it just creates more and more Trojan viruses on my computer.

Microsoft Defender has incorrectly introduced a false positive detection for RPH in a recent definition update. If you're affected, you'll see RPH briefly mentioning 'Verifying Hook' and crash. It may not be sufficient to just exempt your GTA folder; To start RPH, it may be necessary to temporarily disable your AV. You can re-enable your AV when RPH starts and hooks successfully. Alternatively, you can cease using LSPDFR/RPH and wait for Microsoft to fix the problem.