A friend just told me that this should no longer work from 2021. Is that correct? If so, does this also apply to models that have already been sold? For example, I have a Huawei and I need Android for something specific. Then I would have a problem now.
I do not think so. The manufacturer won't let itself get down that quickly. Accordingly, resort to alternatives. From Android to HarmonyOS or Linux instead of Windows.
Older models will no longer receive too many updates. New models are sold without a licensed Android.