Having an accordion teacher who also performs on accordion is the ideal. I say this because too many piano/keyboard players who never played an accordion themselves claim that they can teach accordion, at least in countries where ‘accordion’ means PA. Finding an accordion teacher who plays accordion and is within an hour’s travel can be a chore.
The next alternative would be to find a teacher who gives lessons via Zoom, Skype, or similar service.
Failing both of these, Palmer-Hughes on your own is a good series — up to a point, and that point varies from one learner to another. Method books have weak points that only personal contact with a teacher can overcome. For example, suggested fingering in a method book doesn’t work well for every learner, but a good teacher can spot a problem in fingering for a specific learner and modify the printed fingering so that learner can get over a sticking point. That same teacher can, later on, teach a learner how to figure out correct fingering on a specific piece of music for themselves.
There are other examples of how a teacher can work to help a learner overcome a weak point in a method book; too many to list them all here. But I can give you this one: a teacher can also help to choose supplementary materials at the appropriate stages of a learner’s development.
Finally, learning to play accordion, or any skill set for that matter, shouldn’t be a solitary process, or even restricted to a teacher-learner experience. Participating in a forum like this is a great way to gain advice, get encouragement, and have a sense if companionship.