As far as I know, there isnt any Tool regarding this (yet)

https://github.com/wescode/lemmy_migrate calls itself “migrate”, but judging from a quick glance at the code it takes one primary account and adds all the subscriptions the primary has, but the secondary doesn’t, to any number of secondary accounts.

So it’s really a one-directional sync without deleting.

If you were using Apollo you could export a list of your subreddit s and import it to wefwef.app (currently the best client for mobile)

It’ll still take you time to migrate over, but in the end it will be worth it. Remember, with Lemmy YOU do the organization - there could be multiple instances with your favorite subreddit, it’s up to you to pick what you want.

Don’t blindly consume content, be picky.