Although it has nine pins and you only need three pins, the old computer "D" style connectors are often available on used and scrapped items. They offer the benefit of a solid connection, backshell options for wire strain relief, optional screw locking, and common availability. In addition they are often available with cables attached.
Of course, in some areas no obsolete or discarded hardware is available.
A second common alternative is the five-pin (DIN) circular connectors such as have been used for both keyboard and audio connections for many years. They are an easy to handle size and big enough to be easy to install without needing a magnifier. And they do not match any of the current products so accidents are much less likely.

“Small“ was a requirement, but perhaps mini DIN would work.

 

could be... if polarity and voltages do not match... the way i read it this is not a USB application so there is no need for PD protocol chips. since this is just a sensor, it should be easy to protect. but since the specs and actual arrangement are not known i am not going to try guessing.

Avoiding the use of a common power connector is definitely the best choice. The destruction that can be caused by that is quite impressive. and expensively total, sometimes. So certainly avoid a USB. The round "DIN" connectors are available in a very large number of patterns and sizes, produced by a number of companies. A vastly better choice.