eos.getActions() is actually a wrapper of /history/get_actions RPC API which is provided by the history_api_plugin of nodeos. For this API endpoint, account_name is the name of the account who signed and sent this transaction.
https://developers.eos.io/eosio-nodeos/reference#get_actions-1
In your case, you are recommended to utilize mongodb for query purposes. You can checkout the mongo_db_plugin for nodeos. (https://developers.eos.io/eosio-nodeos/docs/mongo_db_plugin)
With mongo_db_plugin, you can save all the action data into your mongodb instance and query anyway you like in mongodb.
Btw, history_api_plugin is deprecated since eosio v1.2.0 and may be removed in the future. You should consider starting your migration before it's too late.