I benefited from them, but it may be hard to find one that works for you. I joined a Adult Children of Alcoholics (& Dysfunctional Families) group, ACoA. Mine was moderated by a therapist. The degree of religiosity and adherence to the program probably varies the experience between groups quite a bit. As an atheist, I had to do a lot of mental gymnastics around the "higher power" concept, but I don't think it really hampered my usage of the rest of the material.
In the post-COVID era, I suspect that online-only groups have become even more common. Having done both, I would not recommend them. In-person is still the best way by far.