With a full custom loop with 2x 240mm rads, my Ryzen 3700x idles between 32-40 normally with a 22° ambient.
Liquid cooling, whether aio or loop has multiple different properties, involving the rad, the tubing, the pump itself, the cold plate etc. Increasing flow rate may or may not have any affect.
Coolant has a very large capacity to absorb the heat given off by the cpu. Think of it like a line of ppl carrying buckets and you have a hose. The water comes out of the hose into the bucket of the first person starts filling it and moves on, then empties the bucket into a tank. It's not going to matter if the bucket is ¼ full or ¾ full, the tank only gets filled so fast. The flow being the length of time they stood with you waiting for water. Making the line move faster, the buckets are less full. End result is same amount of water is dumped into the tank, no matter how fast the flow.
Moving to performance from balanced changes not only the pump speed, increasing flow, but also changes the fan curves. The fans spin slightly faster at idle and will get faster, sooner. That pushes more air, harder through the radiator, making it more effective at removing the transfered heat. That in turn keeps the coolant at a lower temp, which makes it easier and faster to transfer the heat from the cpu to coolant. Cpu temps go down.
That's the basics, there's a lot more involved, such as ambient temps, case temps, location of rad, push or pull fans, fan speeds, fan types, size of tubing, loop resistance, head pressure etc.
As I said, the job of the cooler is to maintain the temp of cpu within acceptable limits. I should clarify, those limits are what's acceptable to the cpu, not you personally. The cpu decides if it's too warm or not and will increase fans or flow or lower clock speeds and/or voltages accordingly. Your input to the cpu determines by how much that happens, by settings like silent or balanced or performance which are presets, or custom which is manual manipulation.
Fan curves are personal, and different to everyone, unless using a preset. You can set whatever starting temp you choose, with whatever fan speed you choose, with whatever ramp up speed according to temp you choose. So you could set the fans to spin at 80% from 0-60° and an instant climb to 100% at 61°+. Or set fans at 40% at 20° with a long slow ramp up to 70% at 90° only going to 100% at 91°+. Or anything else. Totally your choice.
I generally start with Silent mode, see how it performs, and then modify that to my taste. Asus, and maybe other software, has fan recognition in its software, so using that it can discover the properties of the fans and help with tailoring the fan curve. Presets are nice and simple, but I find custom settings are generally better all around.