Yes, @siemassie is correct on this. To run iobroker, delete all previous volumes for a fresh start and install buanet/iobroker. You can install it in Host-mode. It will then be reachable (after a few minutes!) under [iHost-IP]:8081.
If you want/need access to files within the docker container, you can follow the instructions posted by @Teki
This involves creating all needed volumes first, then installing Filebrowser and then the containers with the applications. If you choose to do so, you can map /opt/iobroker to a certain volume. This will contain all config files.
But I’d like to get back to Home Assistant: I have HA running with editable configuration files and HACS installed. This works. So you can install ingerations via HACS. The only thing missing, is “add-ons”. But in HA they are a sort of separate container anyway, so you could install those add-ons in a different container, right? iobroker is great, but if you are used to Home Assistant, you might as well go for that.