By reading the library and processor/peripheral documentation, changing pin assignments, etc. Spend some time searching the web for similar issues.
ok, I'll change the pin and see if it works.
I suspect a timer is being used that's interfering with your servo control.
With the ESP32, there are only 4 timers and with pwm you get only 8 unique frequency and resolution options. With this library you get the ability to choose any of 16 channels, servo easing, inverted pwm and much more. No issues with the ESP32, ESP32-S2, ESP32-S3 or ESP32-C3. Over 7,000 downloads on PlatformIO.
Here's your code on Wokwi (I've added a quick test in setup) ...
Note: I chose channel 4 which uses timer 2 (see table on library link). Probably timer 0 and maybe timer 1 is being used by other attached libraries (they like to use the first available timer or channel), but I didn't investigate what's actually being used. If this fails, try ch 6 or 7 which uses timer 3.
Here's a servo easing example using pin 18 ...
You precisely diagnosed the issue and the solution you provided worked like charm.
Thanks alot.