The current search Hosts by facts functionality is not very flexible.

For example, there is generally no need to search by fact "uptime==1 day"

However, if it was possible to search by selecting the uptime fact,
and by entering in a text field:

"< 2 days"

This functionality would be more useful where facts have numerical values.

Do you think this can be implemented?

I will give it a try and submit code in a few weeks.