According to our review, 250W peak is about what you can expect from the 5700XT. AVG is around 225. The 3700X is ~100W, so the big two will chew up ~350W between them. Gaming load for a system should be ~400W. A real quality 550W should handle this, a 650W will handle OCing if you want to do that. Depending on which "650W Gold+ PSU" you pick you'll either be fine or hurting badly.
Riotoro is run by guys from Nvidia and Corsair. The Enigma G2 is made by Seasonic and based on the Focus Plus Gold series. Should be pretty good. The Enigma 850 (2017) was reviewed over at JG and scored well. The G2 is a fully modular version.
From what I've made out on here, it's based on a Seasonic Focus which is a solid PSU, it's got enough wattage to adequately supply a upper mid streaming and production rig, it uses great capacitors, it's got a 10 year warranty and it's fully modular for £55.