I have been both a volunteer and a volunteer manager!
In my opinion, you can't be a Volunteer Manager WFH - you need to be onsite, with the volunteers.
There is a lot of truth in the comments above, but that shouldn't lead you to believe that every volunteer is difficult. However, it only takes a few tricky ones to cause chaos.
You need to work for an organisation that seeks to operate in a professional way, and is willing to lose volunteers in order to raise standards - such organisations do exist! They also need to be willing to embrace modern technology and management techniques. It starts from the top, so this sloppy approach of "we'll take anyone, because they're free" is definitely not OK.
There was a fantastic book published some years ago called "Voluntary Not Amateur " which summed up the need for professional standards in the volunteering world, albeit that the vols themselves are unpaid.
There is often a high turnover, so volunteer recruitment is a continuing activity.
You may also find that the old saying that "20% of the volunteers do 80% of the work" can be true.
Depending on the organisation, and the reasons vols have for volunteering, there may be a need to support vols with special needs, or simply to provide emotional support for vols with struggles in their lives.
Working with volunteers can mean a lot of evening and weekend working, because those are the times when the volunteers are available.
Also, be aware that Volunteer Managers are generally underpaid for what they do, and are often expected to muck in with other tasks in the organisation. You need to be committed to the organisation and prepared to make a few sacrifices - don't just do it because it's part-time and (you think) you can work from home.
Having said all that, I really enjoyed it!