In my experience, tutors are most commonly used in home education communities when GCSEs or other qualifications are in the picture, when a parent has been pushed into home education by circumstances, or when there is a particular concern - some just want a few sessions to get another perspectives and tips on what they can do moving forward. The first two would probably be easiest for a secondary school teacher to offer, for the last, you'll want to research home education resources to be able to make recommendations beyond the typical BBC Bitesize and stuff more aimed at schools.
Few home ed learning groups last long term, it's more a term-by-term if that sort of thing, but ones for older kids for qualifications (especially online these days) tend to have more staying power.
However, right now and for the forseeable future, many home ed groups aren't running at all and isolation is more of an issue than ever and with teens it tends to be more of an issue even pre-COVID as most home ed groups are mostly younger kids for a variety of reasons. Running a teens' online home ed group covering particular topics whether it's more traditional tutoring of a subject like the sciences (that, English, and Maths are the most common ones I've seen requests for a tutor for) or a more PSCHE/adult life skills and discussion group could have potential, though as home educators are more likely to be on one income, pricing it right would play a big factor. British resources for the latter are also slim on the ground and so making those might be an option for you (many British parents, home educating and not, can tire of very American resources).
Many home ed groups use facebook - they're not usually open to people only selling services or products, but if you can contact the admins, they might let certain ads or surveys for information through. That's really group dependant - some are really open to it, some it depends, and some it's automatic no.