I am one of the user that switched over to Lemmy, just because of Sync. I heart about Lemmy when I opened Sync for Reddit in July, when it wasn’t working anymore. But app showed a message, that Sync for Lemmy is comming. So I created an account on Lemmy. Regarding automatic update over old Reddit app I don’t think so. I think it has different package name than Sync for Reddit.
Thanks god I have unlimited 150/50 4g internet at home for around 42€ per month. This month we downloaded around 5.5 TB of data. Also small town, countryside, no stop lights, no businesses other than bars and shops. There is only one stop light in whole region. And whole region is getting fiber optic. We had DSL, but speeds were terrible.