In general its not recommended to run Docker inside a LXC, especially for a beginner. However plenty of people (including myself) are doing it, you just might run into a few hurdles.
If you plan on having mostly a single Docker host with your containers running, then i would suggest a VM for that.
If you want to run multiple hosts separately, then the overhead from each VM adds up and i would recommend separate LXC instead.
This gets asked often, you could simply search for existing threads.
If for example he wnats 1 vm with all docker things inside wouldnt it be better to just install drbian and rin docker inside. Instead of running a vm in promix that runs docker?
Just take the tteck script for alpine docker and portainer, very lightweight. I even use one for each docker service and then just backup/restore on the full Proxmox container level.
I have all my docker containers in a vm and then anything not docker in a lxc. For a while I didn’t have issues with docker containers in lxc and then they all stopped worked every time there as an update so I moved them to vms.