Is it possible to detect specific UVB wavelength ranges using just a UVM-30A UV sensor or similar

Obviously this sensor is sensistivy for UV-B and UV-A radiation (even more sensistive for UV-A than for UV-B).

Therefore: no you can not just use this sensor.
At least you need also a filter that blocks UV-A but passes UV-B (using a monochromator would be total overkill; as it requires not only a prism or grating but also some collimating elements like mirror or lense with elaborate setup)

The device is sensitive to wavelengths to 240 to 380nm. Yes, it will give more current per watt of incident light for higher wavelengths. But you'd need the intensity (in watt) irradiating the sensor to calculate the wavelength, and if the light consists of many wavelengths over a wide range, this somehow combines (but not necessarily adds up) to a total current.

So no, this doesn't work.

If you only need to detect a very specific, fixed wavelength range, you could use a filter, though the challenge is to find the right one, which lets only the desired wavelength range pass.

The monochromator mentioned in the comment could be a prism or a lattice and an aperture, which splits the wavelengths spatially. (A prism making rainbow colors from white light is exactly this). By placing the sensor at a specific position, it will only receive a specific wavelength range.

Maybe, you have a look at spectrometers. These typically have an array of sensors, instead just one, which allows to measure the entire spectrum at once.