Fujifilm X-T100 has a 24.0MP APS-C (23.5 x 15.7 mm ) sized CMOS sensor . On the other hand, Fujifilm X-T30 has a 26.0MP APS-C (23.5 x 15.6 mm ) sized BSI-CMOS sensor and features X-Processor 4 processor.
Another difference between these two cameras is that Fujifilm X-T30's sensor lacks anti-alias (Low-Pass) filter. Removing anti-alias filter increases the sharpness and level of detail but at the same time, it increases the chance of moire occurring in certain scenes.
Below you can see the X-T100 and X-T30 sensor size comparison.
Fujifilm X-T100 and Fujifilm X-T30 have almost the same sensor size so none of them has any significant advantage over other in providing control over depth of field when used with same focal length and aperture.