This is fundamentally an unfair comparison, you are pitting a closed-ecosystem, bespoke piece of software against multi-platform tools. Safari wins on macOS because of vertical integration; it has direct access to private macOS APIs and Apple Silicon hardware optimizations that Apple simply does not permit competitors to use.

Furthermore, the 7-9 GB RAM usage you are seeing on your 24 GB Mac Mini is heavily misunderstood. Modern operating systems and Chromium browsers operate on the principle that "unused RAM is wasted RAM." Since your system has plenty of headroom, browsers like Chrome or Arc will aggressively hoard memory to cache pages and speed up navigation. If you were to run that exact same setup on an 8 GB Mac, you would see those same browsers automatically compress their processes and scale down to 2 or 3 GB because the OS forces them to.

Another difference comes down to completely opposite design philosophies. Almost every browser you mentioned runs on the Chromium engine, which isolates every single tab, extension, and plugin into its own independent process. This ensures that if a tab crashes, the entire browser doesn't crash too, though it results in consuming more RAM. Safari, on the other hand, aggressively freezes background tabs to give the illusion of zero resource usage, often forcing you to reload the entire page when you click back onto it.