For extremely low-end PCs (1-2GB RAM), Unity 5.6.7 is lighter and fully 32-bit. It lacks modern features like Shader Graph but runs on Windows XP SP3 and Vista.
Warning: Never download "cracked" or "portable" 32-bit Unity versions from torrent sites. They often contain miners or ransomware. Unity 3d 32 Bit Download Free
If you manage to install the last stable 32-bit release (typically found within the Unity 2017.x or Unity 2018.x cycles), here is what you can expect: For extremely low-end PCs (1-2GB RAM), Unity 5
⚠️ Using outdated software (especially from unofficial sources) exposes your system to known vulnerabilities. Only download from official Unity Technologies sources. Warning: Never download "cracked" or "portable" 32-bit Unity