It’s possible… there is this in the trigger data - Monzo.cardPurchase.Category
There is an applet already for all Transport card purchases: Redeem Transport spending from a pot - IFTTT
And this one for all Grocery card purchases: Redeem grocery purchases from a pot - IFTTT
And this one for all Eating Out card purchases: Redeem Eating Out spending from a pot - IFTTT
And this one for all Entertainment card purchases: Redeem entertainment spending from a pot - IFTTT