Was reading reviews of some of the power supplies sold here and some complaints the output was messy. I forget the terminology.
US $201.60 20％ Off | Adjustable Switching Power Supply 2000W 0-12v 24V 27v 36v 48V 50V 60V 70V 80V Digital display LED Power Supply
https://a.aliexpress.com/_mq44D1e
How important is it?
A couple hundred mV of electrical noise shouldn’t affect anything but some supplies go over a few volts of noise at high voltage/current levels. That could be a problem.
The pack itself won’t care much as long as the spikes from the supply aren’t crazy high but a BMS might not like being forced over its voltage rating even if it’s just spikes/noise.
The hard part is finding out how bad any particular model of power supply really is.