Is a 750W power supply too much for this build?

Yes, it's safe. The 750W rating is the maximum the PSU is designed to supply, not an amount it forces into the PC. Your components draw what they need.

For a small price difference, the extra capacity can be handy if you upgrade later. A 650W unit could also be plenty for the current build, assuming it's a suitable, good-quality model.

A bigger rating doesn't mean the PC constantly pulls 750W from the wall. The PSU does use some extra power because conversion isn't perfectly efficient, and efficiency varies with load. So two different PSUs can produce slightly different electricity use with the same components.

That doesn't mean a 750W unit will suddenly make the bill skyrocket. Look at independent efficiency measurements for the specific models if running costs are a concern.

I'd look at the exact PSU model and its reviews before chasing a bigger number. Wattage alone doesn't tell you about build quality, protections, noise or warranty. Check that it has the connectors your RX 580 needs too.

The MSI MAG A750GL may fit what you're looking for, but compare independent reviews of it and the A650GL rather than assuming either is good just because of its brand or wattage.

The 750W makes sense at only a few dollars more if you expect to keep it through an upgrade. Just don't treat it as a guarantee for every future GPU. Check the requirements of whatever parts you eventually choose.