Search forms in UNA are customisable for your requirements. In UNA.IO there is no refinable search forms to search for other members, because that is not what this site is about. But on an UNA based dating site (for example) you can customise forms to search for age/location/gender etc.
As an admin in UNA I can search accounts and profiles under some criteria, this ability is not available to general members, but in your own site, if you deemed it appropriate, you could extend that ability to all members.

Bear in mind that UNA is a framework,  so there is no rigid fixed way of configuring your site. UNA.IO is just one of many possible configurations built upon the UNA framework, so this site only demonstates a fraction of the potential available with UNA.
Have you watched the full UNA Demo here? - https://youtu.be/hhdog8nLjEk