For years Beta has been using 3rd-party speedos with bezels modified to accommodate Beta-specific indicator lights and associated wiring (i.e. warning for low level in the oil tank and ECU detection of OI system failure etc.)
2013-2016 bikes used a modified Trail Tech Enduro II.
2017-2019 bikes used a modified Facomsa Everest.
2020-2021 bikes appear to be using a modifed
KOSO EX‑02S Street Version speedo.
I have no knowledge whether the KOSO speed sensor will work with the Beta version, but my guess is that the chances are good.