I try to build a docker image for my raspberry pi 4b which supports 64bits arch, but OS installed is 32bits (I can’t change it).

uname -a
Linux raspberrypi 6.1.32-v8+ #1656 SMP PREEMPT Wed Jun  7 11:37:17 BST 2023 aarch64 GNU/Linux

getconf LONG_BIT
32

I build the images on Windows 10 using desktop-linux builder.

docker buildx inspect
Name:          desktop-linux
Driver:        docker
Last Activity: 2024-08-19 11:26:09 +0000 UTC

Nodes:
Name:             desktop-linux
Endpoint:         desktop-linux
Status:           running
BuildKit version: v0.13.2
Platforms:        linux/amd64, linux/amd64/v2, linux/amd64/v3, linux/arm64, linux/riscv64, linux/ppc64le, linux/s390x, linux/386, linux/mips64le, linux/mips64, 
linux/arm/v7, linux/arm/v6

Dockerfile

# FROM --platform=$BUILDPLATFORM alpine:3.18
# FROM arm32v7/alpine:3.18 #prolly the same as next line
FROM --platform=linux/arm/v7 alpine:3.18
# FROM --platform=linux/arm64 alpine:3.18

[...]

# Set the default entry point to run the Node.js application
ENTRYPOINT ["node", "dist/index.js"]

# Additional CMD to start Bash if needed
CMD ["/bin/bash"]

My private docker repo (192.168.8.x:) works ok (tested with other images)

docker buildx build -t 192.168.8.x:<port>/myapp1:v100 --push .
# I add --platform linux/xxx when using $BUILDPLATFORM

docker-compose.yml on the raspberry

version: '3'

services:
  myapp1:
    #platform: linux/arm64
    container_name: myapp1
    image: 192.168.8.x:<port>/myapp1:v100
    ports:
      - "3000:3000"
    restart: always


  myapp2:
    #platform: linux/arm64
    container_name: myapp2
    image: 192.168.8.x:<port>/myapp2:v100
    deploy:
      resources:
        limits:
          cpus: '0.6' # Limiting to 60% CPU usage
    environment:
      MYAPP1_URL: http://myapp1:3000
    restart: always

docker run <imageid> //or docker compose up -d

WARNING: The requested image's platform (linux/arm64) does not match the detected host platform (linux/arm/v8) and no specific platform was requested

In portainer I can’t get the logs as container is always restarting
I either get
No log line matching the '' filter
or
exec /usr/local/bin/docker-entrypoint.sh: exec format error

What am I missing here?
Thank you