I'm using Sitecore 9.1 and SXA 1.8, Is it possible to boost the search results by a specific field value, what I see in SXA boosting rules that you adjust boost by adding a value statically, I want it to be dynamic based on a field value.
Not all of them are static. Take a look at the whole list of supported boosting rules, in the end, you will find some SXA rules:
They are not dynamic as they are e.g.: comparing the field to the page field.
The other thing is that you can write your own rule is none of the existing suits your requirements. Check how SXA rules are written. There is an SXA specific pipeline called
resolveBoostingQuery where you can add your custom rules. Take a look at how
ResolveFieldAndQueryMatchRule are implemented.