Can you please let us know if you are looking for form factor compatibility? In that case, you are correct, the DEMO DISTANCE2GOL is Arduino header compatible whereas the DEMO BGT60LTR11AIP is Arduino MKR header compatible. The DISTANCE2GOL comes with an XMC 4700 baseboard that runs the Distance2GoL firmware.
Both these radar boards are 3.3 V compatible and can be used with an external microcontroller. These training videos should help with your query -
Additionally, you can refer to the Distance2GoL (Software-Controlled FMCW radar) software user manual for information regarding the Distance2GoL firmware.
Please let me know if you have any further queries.
Rakshith M B