Hi Charles,
What you are looking for is a so-called level-shifter. See this one for example: [url]https://www.adafruit.com/product/1787[/URL]. A HEF4050B won't work properly.
You will need to power the chip with 5V [as you do with the WS2812 LEDs].
The chip will accept 3V3 signals as input. And will output 5V signals.
Be careful with wiring up the chip: don't let the 5V power or outputs contact the Teensy 4 pins - your Teensy will be fried.
Paul
Yes, it's a level-shifter but is used for handling input voltages larger than its power supply voltage.CD4050 is not a level shifter?