woofer positioning in the cabinet

[weltersys]

This attached is the old design, if it is not a problem of orientation / proportions of the cabinet, on which aspect do you think I should focus?

Damping on the back of the cabinet to reduce mid band reflections emitted through the large port areas.
Crossover and equalization.

It seemed like an important aspect to take into consideration because doing some simulations with Hornresp, I noticed an increase in resonances, while increasing the depth.

Did you notice any difference in frequency response?

For example when in the song by Adele - Rolling in the Deep, let's say the bass line starts, I have that feeling of confused sound.

Could be room issues.

What types of measurements can be useful to try to understand?

Frequency and phase response of the individual components (including the port) and combined response, preferably outdoors to eliminate the room response.
Vertical and horizontal on and off axis measurements in 5 degree increments out to 180 degree off axis.