I have the exact same issue…
I am able to pull the shutters up and down, but I can’t set a specific % level like with dimmers. Meaning I can’t use cards like this either. GitHub - Deejayfool/hass-shutter-card: Shutter card for Home Assistant Lovelace UI

I am a n00b when it comes to MQTT and have this setup mostly to get a proper dashboard for my Homey, but it would be nice to have this feature…
Any suggestions @HarriedeGroot, is there a quick fix?
I have the Fibaro Roller shutter 2.