Migrating Chat data from one phone to another?

[utuser]

Hi all,
I'm using two vollaphne devices running UT (2020 and 2022 ed.). On both devices axolotl is running fine but with different SIM cards.

I'd suppose it is not possible to use one app with two SIM cards? Is the app only linked to Signal via the IMSI or also via the IMEI? If only IMSI: which directories/data would have to be copied?

If IMSI and IMEI: I suppose both apps have to be de-registered and re-registered with the desired device? But can existing chats then be (manually) imported?

Thanks for your advice and support!
Mat