What's the most effective thing Celts can do vs Britons 1v1 arabia?

Or any infantry civ like slavs vs them

The high range crossbow blob seems like a pain in the ass to deal with

As the infantry civ I do 3 militia drush into hoang push. But I feel like mangonells are a big investment with a hit or miss return (literally) so I'm thinking of doing something else

Thinking of going drush into scouts and skirms

Or should i go to imp and mass garrisoned rams

I'm beating lower elo britons and Ethiopians easily but it's a hard matchup with the higher elo guys who want to get a blob of crossbows in castle then early imp push with arbs and trebs before my best options come online. Feel like skirmishers, onagers and scorps are outranged or outgunned so i feel like its either rams or castle age hoang rush or a feudal heavy scout skirm

So what's the most effective?