Never had a 5G phone - I assume they must be backwards compatible with 4G LTE and

3 G?

 

I.e., if 5G not available phone will use 4G LTE, if not available will use 3G.

Never noticed that there is a 5G only phone.

Would be worthless.

Of course in most cases they will fall back to 4G/LTE which is the basic coverage over the country.

3G either abolished or in the process. 

 

Usually backwards compatible but not necessarily supporting bands you need for your telecom.

14 minutes ago, tomazbodner said:

Usually backwards compatible but not necessarily supporting bands you need for your telecom.

My simplified assumption: it's about buying a new 5G phone in Thailand for use in Thailand.

15 minutes ago, KhunBENQ said:

My simplified assumption: it's about buying a new 5G phone in Thailand for use in Thailand.

In Thailand or online probably via the Lazada Samsung store.