Question Is this a good rig for triple A/heavy demanding games?

The main limitation with that system is the use of an unspecified psu. It states 600w, which means nothing. The manafacturer is likely a cheap Highpower unit or similar and would need replacing.
The second thing is that the system is on a b365 motherboard, the max ram speed for b365 is 2666Mhz and will likely not be able to handle a 9900/9900k if you were ever to upgrade. It's also fair to note that 1151v2 is a last gen socket, the current socket is lga1200, and in a year it'll be lga1700.

Even with all those things, it's still a pretty solid and will work fine for your applications, just don't stream with it as well.