Delineate between low, medium and high value 'unspecified' values.
If the value of an opportunity is below say $9,999, between $10K-$49,999 or >$50k in a currency they could be grouped, so that we can filter out low value unspecified opportunities, but not miss the high value ones.
For many researchers their search contains a high number of unspecified value opportunities, and to manually go through all of these to see if they are of high enough value to be of interest for Mid and Established researchers is off-putting for researchers.
If there was a filter by value group, they could only include ones of high value, and filter out the low value ones that are clutter and waste time (like $500 or other low-vale awards).
If they were at staggered values students and researchers could include the value thresholds that are relevant to them.