Tact switches in the same size 12x12x3mm, same form square plunger, are made in a range of activation force. Omron makes several versions.
The original Botvac switches were measured by pressing with a postal scale at 170gm.
Compare to Omron
Many different switches are listed at parts distributors such as Digi-Key. Search for particular models on ebay and Aliexpress. In Europe, electronics distributor Mouser has facilities maybe avoiding expensive postage from Digi-Key U.S.
Given how the Botvac mounting involves a compression spring to press the tact switch, high activation forces may need to be avoided. The spring would have to compress much more to activate the switch. The mechanism design is specifically calibrated.
There have been reports of deterioration of the compression spring. Hard to find an exact replacement, most much harder. The Botvac design is not the best: they should have used a mechanical stop on the actuator at the switch activation distance, less dependent on the precise spring pressure. Neato Robotics seems to have changed the mounting details a couple of times. The oldest simple bending strip of the housing was unreliable and not permanently flexible, creating stuck switches. The material is softened by heating as with a clothes iron, hair dryer etc.