5V pin out, 8 pins and micropython/circuitpython support: does such a board exist?
Both your &quot;requirements&quot; for the board are non-requirements.

You do not need PWM pins to drive Neopixel strips. The Neopixel uses its own custom protocol that has nothing at all to do with PWM.
Your board only communicates with the first Neopixel. That one then communicates with the second, which then communicates with the third, etc. The length of the strip is completely irrelevant to what voltage you might want to drive it with.

You only care about having enough general IO pins and if the IO voltage is suitable to communicate with one Neopixel.
According to the WS2812B datasheet VIH is 0.7Vdd, which if you are powering the strips from 5V means 0.7 * 5 = 3.5V. However I think that is an overestimation and they are erring on the side of caution there, since I regularly drive WS2812B strips from a 3.3V microcontroller with no problems whatsoever (after all it's only 0.2V difference).
So just use your favourite 3.3V microcontroller that can run micropython and, if you really want to, drop the power supply voltage to the strips a fraction with a diode.