I was thinking about a nvme SSD + a casing.
Do you know what casing would be suitable? Where/how to find it? I'm in Europe.
I'm getting just over 400MBps read/write over usb.
Be cautious with your choice; many NMVe enclosures are fine as external disks but not as ones running macOS. For example, ICY BOX form Germany as enclosure for NVMe M.2 is a nice choice but NOT for running macOS. For that purpose I use Samsung T7 on practically all my Macs. The newer and faster T9 models won't do on Macs, though. (All those models come with both USB 3 and USB-C cords.)
