When disabling target filters in the config, you still cannot target players and harm them with hostile spells.

Minecraft: 1.20.1
Mod Version: 0.13.3
Fabric: Latest

I don't understand sorry. What are target filters?

Here is what the FAQ says.

Why can I not hit other players or villagers with area spells (like Arcane Beam)?
The default configuration is PVE oriented, friendly towards villagers and other players.
Put players into different teams to allow hurting each-other.
Alternatively you can change this in Spell Engine server config (config/spell-engine/server.json5)