Where to obtain Windows XP in 2025?

I am putting together a retro PC from the XP era and haven't used XP in at least 10 years. I have since tossed all my OS discs, but also know XP is insecure to use now. I heard you can install an unofficial SP4 to get it much safer though. Anyway, where is a legit/"safe" place to get an XP installer or ISO that is "secure" that isn't going to be full of malware? I am just trying to run old benchmarks and a handful of games, but would like to be online. Any advice from those running XP on retro PCs welcome, this is my first one!