Have you thought about getting a user's licence for Sketch engine- https://www.sketchengine.co.uk- and uploading your corpus onto this platform so that you can use the different tools available there?
Sketch Engine allows you to search for collocates using different statistical measures-log-dice, T-score, MI score etc- and with different settings with regard to the number of spaces between your search word or string and potential collocates, the number of times a word must co-occur with your search word in order to be considered a collocate, the overall minimum frequency of the collocational candidate across the whole corpus etc. As far as I know, these functions, and others related to frequency, concordancing etc will work with corpora that you upload as well as with pre-loaded corpora, but you'd need to look into this.
If you don't wish to pay for the licence yourself, maybe your university already has an institutional licence for Sketch Engine or would be prepared to consider getting one.