MBB tend to hire more PhDs than other firms indeed (exception being PhDs specializing in healthcare, for which companies like ZS, LEK, IQVIA and ClearView also actively hire). However, you may still have other options. The following are some companies other than MBB for which I helped PhDs to prepare in the past:
You may review also other strategy consulting firms (eg RB, Kearney, OW) but not necessarily all of them will accept PhDs (HR or current consultants should be able to point this out). There may also be differences in acceptance or not based on your geography.
Hope this helps,