Alternative for formula field if it doesn't allow more than 5000 characters

I need to create a formula field that updates a checkbox after verifying Company's value. I couldn't complete creating a formula field as it throws an error that the limit is 5000 characters. I want to query many company values and update the checkbox. Can someone please suggest an alternative to achieve this functionality?

Can I create a trigger or apex class? 

#Sales Cloud #Analytics #Automation #Integration Would creating that be affected by character limits as well?