I don't have any advice for handling the change with your in person therapist, but I can speak about online therapy. I switched to online in June and I think DBT could be done online if you are highly motivated and able to express yourself openly and honestly without the pressure of in person interaction. For instance, if you rely on your in person therapist to "fill in the gaps" or "know" when you aren't being 100% truthful based on your body language, then DBT online might not work for you. I think it would only work if you're willing and able to be extremely honest and say things like "I didn't do the work, I couldn't do it because, I am struggling with it because (specific reason)"

Just my opinion though! I think the biggest downfall of internet therapy is that the therapist can't tell when you're lying. You have to call yourself out on everything if you want to make progress.

Sorry to hear about your in person T suddenly changing methods to one that you aren't connecting with.