Hello,
The read range which can be achieved will mainly be defined by the used antenna size. The bigger the antenna the bigger the read range will be if there is sufficient coupling between reader and tag antenna. In other words if you increase your reader antenna and have a very small tag antenna, the read range might even reduce.
Also the used technology will influence the achievable read range. ISO15693 for example will have a bigger read range then ISO14443.
Looking only at the antenna sizes, the two DISCO boards will give you the biggest read range. The two X-NUCLEO-NFC05/06 boards will have approximately the same read range.
There are several interesting posts which discuss how to increase the read range:
https://community.st.com/s/question/0D50X00009XkWCSSA3/design-questions-around-st25r3911b
https://community.st.com/s/question/0D50X0000Bh5zQqSQI/how-to-use-st25r3911b-for-long-reading-distance40cm
In general I would state the read range of the DISCO's 1-2 times higher then the X-NUCLEO-NFC05/06 depended on the used technology and card (antenna size and resonance frequency).
Please let me know, if this answers your question.
BR Travis
