I had the Craftsman-branded version of that several years ago.
It wasn't horrible, as just a grinder, but I felt it was severely under-powered after installing and using a wire wheel. The thing bogged down all the time.
It's got a 2.1amp motor, which is going to put out maybe 1/6hp.
I gave it to my brother, who had just bought himself a house and was outfitting it with tools, and bought a DeWalt 6" grinder.
Significant difference, but, of course, twice the price of that Ryobi.
The DeWalt claims 5/8hp, and it's probably close to accurate.
If the speculators and hoarders hadn't screwed up the market and driven up prices, I'd say search Craigslist for an older grinder, such as a Craftsman block grinder.
I was able to pick up a 3/4hp model, pristine condition, like it had just been unboxed, on the original stand, for cheap.
If anything, the rated HP is under-rated, because these things are a beast.
Here's an 8" 1/2hp Craftsman block for $65, so there are still some deals on them out there.
https://bend.craigslist.org/tls/d/bend-craftsman-1-2-hp-bench-grinder/6999686730.html
If that thing wasn't a 3-hour drive away, I'd jump on that for my dad or to upgrade my brother.