To elaborate a bit- conditions evaluate if something is true or false. They do not filter a list that you can use in the next step. If you want to check that a line item has a tag AND the value for that line item is > 25, you need to have those both in the same condition block (click add criteria for same list item to add multiple conditions for a single line item)
If you need to total all of the lineItems that have tags and then check if the total is over $25, the only way to do that is via Liquid in the action itself (as Flow doesn’t have the necessary filter/aggregate tools yet). So you would need to write liquid in the tag field (possible) that loops over the line items, checks tags, adds the values, etc.