Hi Max,
some time ago j developed a simple PWM routine. J used the timer T0 in 16 bit timer mode, ad j used two different reload values for the ON and OFF period of the PWM.
In the isr routine of T0 the code swaps between the two reload values, toggles the dedicated output and this creates the PWM signal.
This is especially good if you need a fixed duty-cycle PWM and don't want to use a microcontroller with dedicated PWM hardware.

However if you need more control over PWM signal you must choose a micro with the PCA or similar peripheral onboard.

Regards