Is it possible to develop SNMP traps handling outside of the proxy and server as a new Zabbix component?
When you have a Zabbix server in HA or a group of proxies, you can have an external Zabbix component that has the logic of reading the traps file and sends the result to the correct active node, either the server or the proxy.
This component can have the property of being in HA, sending what was read in the traps file to the Zabbix DB or to the proxies it reports to. The high availability of the file would be a matter of shared disks on the network with their replication.