Welcome to the forum, Avinunca 
As for Sonoff’s Zigbee based products you don’t need eWeLink. For i.e. the ZBMINI-L2 switches (I use a few of them too) just pair/connect them to HA through Zigbee2MQTT. No eWeLink at all. But obviously you’ll need a suitable Zigbee coordinator like the Zigbee 3.0 USB Dongle plus. Don’t forget to order an USB extension cable with at least 1.5 meter in length to connect the dongle to your HA hardware!
This is different with Sonoff’s WiFi based products. With their WiFi based products you’ll need the eWeLink App for the initial setup (pairing the devices to your WLAN). After the pairing is done you can use something like SonoffLAN to integrate and control those devices through HA.