I’ve a Brompton Explore limited edition 2020) & need a rear rack

I'm wondering what's the best rack to get?
I see the traditional older roller one (silver & black models) and a lighter minimal one. I'm just unsure what will be best.

I've been commuting/using a regular gravel bike for everything as it's got locks as well as rear and front mounted racks on it. Admittedly I've been too lazy to take them off & carry the locks to use the Brompton and too poor to buy a waterproof front bag (the one it came with is great for touring and exploring but absolutely massive for the daily commute to work). Living in Ireland it rains often and I'm looking at also getting the fully waterproof bag that doesn't need a cover.

I want to start using the Brompton more often and having a rear rack would help when touring /adventuring. Can anyone recommend which rack would be best?