So I wanted to post a little something because it took me a second to figure out why my ESP-01 was not booting. I had only used one of these before and it was on an adapter PCB that had the wiring already done on it. But when I made my own PCB for a WLED project I found that it would not boot when powered up over 3.3V.
The issue was you need to supply 3.3V to the CH_PD/EN pin to get it to load the firmware AND you cannot have GPIO0 or GPIO2 pulled low (aka LEDs connected to it). I ended up using the RX pin for the LED control (GPIO3) so I didn't have to install a pullup on GPIO2 or GPIO0.
You can just directly connect the CH_PD/EN pin to the 3.3V pin with no resistor and this works perfectly. If you wanted to install a pullup a 10K or 100K ohm resistor would work fine.
Pic Source: https://www.theengineeringprojects.com/2019/05/introduction-to-esp-01.html
If you look at the table below you can see if 0 or 2 are pulled low (connecting neopixels to those do this) then you'll need a pullup resistor to pull them up to 3.3V. If you use the TX or RX pins then this is not an issue.
