With Klickfix handlebar mount (fold-comply) there are so many handlebar luggage possibility (Vaude/Rixen&Kaul/Ortlieb etc). Got an old Vaude from my touring bike fitted on Bromp : r/Brompton
Cycling Insulated Bike Cooler Bag Water Resistant Bike Handlebar Bag Bike Basket Front Bag Pannier with Bike Phone Mount - Walmart.com
The fun side of Eurobike: Day 2 in photos | DC Rainmaker