My suggestion is that you expand on the necessary requirements - details matter.
Requirements must be quantifiable and specific.
Remember to take a look at your servers - most software lists hardware requirements in the form of "minimum", "recommended", and "best".
For example, RAM = 8GB, 16 GB, 32 GB respectively.
You do not want "minimum" and you do want as much "best" as you can afford.
Here is a link that includes a "checklist":
https://www.sweetprocess.com/knowledge-base-software/
Not sure how much information you may or may not wish to provide to get the checklist.
However, google "knowledge base software" for a broad list of products and listings. You will find many links and reviews.
And set a budget value beforehand : "not expensive" is relative.
Then, as you read and learn, revise your search criteria to focus in on products that appear to be a good match to your business and business requirements.
Hopefully you can get trial versions to test - determine if the software does indeed meet your requirements. Likely you will need to make some trade-offs.
Just my thoughts.....