Ive done thousands of wire nut connectors. If not ten thousand.
I can count on one hand the number of 'failures' that pass me by. A wire is not fully seated and doenst get bonded in the 'twist'...or a wire breaks. (Usually I catch these issues immediately, as the wire is manipulated back into the box....)
But with a wire nut, I am confident it will handle 20Amps, year after year after year.
Ive done wagos for little lighting circuits, zwave, stuff like that. Mostly when the device comes with the connector.
If the wire fill on the box meets code, Ive not had a problem with space. (although admittedly, Ive only seen space be an issue with X10 and zwave devices that seem to be fill-pigs. Standard switches and receptacles, not a problem.)