Hi @Kubiznak,
Thank you so much for your interest in our products and for using our community.
As such the reference manual is not very clear regarding speed measurement with the ENC module. And there are only examples of position with encoder (twrkv46f150m_enc_basic and twrkv46f150m_ftm_quad_decoder).
However, for low speed measurement, via XBAR you need to connect the ENC_PHA (XBARA_OUT44) and ENC_PHB (XBARA_OUT45) to trigger a general purpose timer to make low speed velocity measurements.
Hope it helps you. Please let me know if you have more questions about it.
Have a nice day!