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I'm new to off road riding.
Then rest assured you will try multiple types of tyres before eventually settling on what works for you, your riding and preferences.
For example riding offroad around London varies massively in conditions based on type of soil and terrain, and even with same conditions different people have different preferences.
Vittoria Terreno/Mezcals are a good place to start. I would say 40mm is plenty if you are not planning a bikepacking trip or to ride very rough surfaces really fast.
Why do you need such width?