I managed to get more info. dmesg shows quite some errors after the filesystem gets mounted.
[ 208.054442] sd 8:0:0:0: [sda] tag#16 uas_eh_abort_handler 0 uas-tag 1 inflight: CMD IN
[ 208.054448] sd 8:0:0:0: [sda] tag#16 CDB: Read(10) 28 00 74 70 67 80 00 00 08 00
[ 208.067472] scsi host8: uas_eh_device_reset_handler start
[ 208.185844] usb 2-4: reset SuperSpeed USB device number 2 using xhci_hcd
[ 208.211526] scsi host8: uas_eh_device_reset_handler success
[ 208.211600] sd 8:0:0:0: [sda] tag#16 FAILED Result: hostbyte=DID_ERROR driverbyte=DRIVER_OK cmd_age=30s
[ 208.211603] sd 8:0:0:0: [sda] tag#16 CDB: Read(10) 28 00 74 70 67 80 00 00 08 00
[ 208.211605] I/O error, dev sda, sector 1953523584 op 0x0:(READ) flags 0x80700 phys_seg 1 prio class 0
[ 210.064310] EXT4-fs (sda1): mounted filesystem cd2725e1-12be-4bff-8bfa-e3000c005144 r/w with ordered data mode. Quota mode: none.
Googling some of these messages led me to believe that disabling UAS for this device could solve/mitigate the issue. It doesn’t really solve it, but this time there’s only one error.
[ 109.379041] sd 8:0:0:0: [sda] tag#0 timing out command, waited 60s
[ 139.804014] usb 2-4: reset SuperSpeed USB device number 2 using xhci_hcd
[ 141.675471] EXT4-fs (sda1): mounted filesystem cd2725e1-12be-4bff-8bfa-e3000c005144 r/w with ordered data mode. Quota mode: none.
To be sure, I checked on Manjaro and none of these errors are present there.
I can’t really find any useful information on the internet about what the issue could be in my case.