It is a direct wiring socket, please refer to the manual for wiring method:
https://www.epever.com/wp-content/uploads/2021/09/IPower-Plus-Manual-EN-V3.4.pdf
If you prefer to use some kind of connector, maybe you could try some wire ferrules, just make sure no metal parts are exposed.
https://www.amazon.com/Self-adjustable-AWG-23-7-Electrical-Connectors