Looking for a good quality bike satchel (tired of using rucksack). Any suggestions?

I’m eyeing up Isaraua messenger from MAAP (it’s artistic and sleek and what I’m looking for). But it’s also obviously quite expensive at $345. Any other recommendations around the same price tag? Don’t care about brand, but some nice aesthetics and functionality (bike specific & will hold on my back with the appropriate straps rather than slip around places) would be ideal.