Docker user namespace isolation: permission denied with bind mount - linux

Question

I enabled user namespace isolation as depicted in archwiki and on docker documentation.
However, when I try to use a bind mount:
# this is fish shell
$ docker run --rm -it -v (pwd)/bmount/:/bmount alpine sh
I get:
docker: Error response from daemon: failed to create shim: OCI runtime
create failed: container_linux.go:380: starting container process
caused: process_linux.go:545: container init caused:
rootfs_linux.go:76: mounting "xxxx/bmount" to rootfs at "/bmount"
caused: stat xxxx/bmount: permission denied: unknown.
I managed to get regular docker volume to work without issue. As far as I'm understanding this setup, bind mount should be working given the container has rights on the folder, right?
Here is some more details:
I created a dockremap user and group, both having an UID/GID of 200000
Here is the content of /etc/subuid and /etc/subgid
dockremap:200000:65536
dockremap:200000:65536
And docker is configured to use user namespace isolation, here is the /etc/docker/daemon.json
{ "userns-remap": "dockremap" }
I made sure the bmount folder I'm trying to bind mount is chown to dockremap
drwxr-xr-x 2 dockremap dockremap 4,0K 24 juin 13:08 bmount
docker info gives this:
Client: Context: default Debug Mode: false Plugins: app: Docker
App (Docker Inc., v0.9.1-beta3) buildx: Build with BuildKit (Docker
Inc., v0.5.1-tp-docker)
Server: Containers: 0 Running: 0 Paused: 0 Stopped: 0 Images: 2
Server Version: 20.10.7 Storage Driver: overlay2 Backing Filesystem:
extfs Supports d_type: true Native Overlay Diff: false
userxattr: false Logging Driver: json-file Cgroup Driver: systemd
Cgroup Version: 2 Plugins: Volume: local Network: bridge host
ipvlan macvlan null overlay Log: awslogs fluentd gcplogs gelf
journald json-file local logentries splunk syslog Swarm: inactive
Runtimes: io.containerd.runtime.v1.linux runc io.containerd.runc.v2
Default Runtime: runc Init Binary: docker-init containerd version:
36cc874494a56a253cd181a1a685b44b58a2e34a.m runc version:
b9ee9c6314599f1b4a7f497e1f1f856fe433d3b7 init version: de40ad0
Security Options: seccomp Profile: default userns cgroupns
Kernel Version: 5.12.11-arch1-1 Operating System: Arch Linux OSType:
linux Architecture: x86_64 CPUs: 2 Total Memory: 3.735GiB Name:
CRIQUET ID:
AT7Q:T3HO:HBFF:H7AM:XABE:KY4B:AQ2H:POBZ:YUE3:XGOT:4ROB:SDUX Docker
Root Dir: /var/lib/docker/200000.200000 Debug Mode: false Registry:
https://index.docker.io/v1/ Labels: Experimental: false Insecure
Registries:
127.0.0.0/8 Live Restore Enabled: false
$ uname -a
Linux CRIQUET 5.12.11-arch1-1 #1 SMP PREEMPT Wed, 16 Jun 2021 15:25:28
+0000 x86_64 GNU/Linux