The miner is the same on all three. RandomX, xmrig, P2Pool. Gupax is still the easy door: one GUI, bundled P2Pool + xmrig, primary address (the 4 one), start P2Pool then xmrig. Don't begin in a terminal.
What changes is how the operating system gets in the way.
Windows
Antivirus will quarantine xmrig because it is a miner. Official line: whitelist your own copy, and P2Pool too. Add the whole Gupax folder, not one .exe. Then run it elevated so MSR / huge pages can actually work. If Windows ate the binaries, you're not infected. The miner looks like every other miner because it is one.
macOS
Gatekeeper quarantines the .app because it came off the internet. Un-quarantine it (Gupax README: xattr on Gupax.app). Intel and Apple Silicon have separate bundles — grab the one for your chip. Huge pages are not a thing on macOS. Don't chase that setting. sudo can help xmrig; the GUI path still comes first.
Linux
Usually no antivirus drama. The trap is huge pages left at zero, and xmrig not elevated, so RandomX never gets the memory it wants. Gupax still saves you from assembling p2pool + xmrig by hand. If you already live in a terminal, official docs have the sysctl. If you don't, don't start there.
Same homework after it launches: whose node, primary 4 address, P2Pool. That's a different post.
I hash on spare-parts/new Windows and Linux boxes. Win/Mac/Linux shop talk welcome if you're stuck on Gatekeeper, huge pages, or AV.