ZBXNEXT-3776 tricked me with its subject, as it looks like that topic was about LLD discovery, but I think the same functionality should exist for network discovery.

After looking at debug logs for discoverer process, it looks like this could be easily done;

On each refresh of the discoverer process, it performs the following SQL query;

select distinct r.druleid,r.iprange,r.name,c.dcheckid,r.proxy_hostid,r.delay from drules r left join dchecks c on c.druleid=r.druleid and c.uniq=1 where r.status=0 and r.nextcheck<=1669086313 and mod(r.druleid,24)=4

Would a button in Zabbix PHP that updates the table similar to <excuse lazy code>;

update drules set nextcheck = (SELECT UNIX_TIMESTAMP(NOW()) + 60);

That way on the next refresh the check finds that nextcheck is indeed 

<=(SELECT UNIX_TIMESTAMP(NOW()) + 60)

 and starts discovery? Just spitballing here, but I'd love to be able do to this both from a "hey we have a new rule" and a "verify the rule is working" POV.