Very good idea. I did the same and over the next two years, from this BKK base, explored Pattaya, Chiang Mai, Khon Kaen, Korat, Pechaburi, and Phuket. Saw big cities, rice villages, tourist traps, temples, parks, mountains, islands, and beaches. Then made a choice that lasted for the next 20 yrs. Will hit the road soon again. Remember, test drive your location, and do not *ever* leave a rental deposit that exceeds one month rent (LOS is a religion tolerant country and if you land near a mosque, you'll hear call to prayer thru loudspeakers five times a day starting at 5 am). Also require for the landlord to register their renting to a foreigner. Good luck.
Nothing you can do. This is a recurring problem and those who get lucky keep telling others to ship their stuff over. Somebody just got a free phone, the one you paid for.
They will take your money, so the best choice is to rent month to month, unless you are going to extend your visa based on family, marriage, being over 50, etc, when the IO requires an ongoing lease. Then there was talk, months ago, of the gov forbidding landlords from requiring a 2 month deposit.... don't know what came out of it but I've read posts in this very group about people losing their deposit. Good luck.
Get a third E-mail (or more). I prefer USB sticks and SSD drives. Have >500 Gb of data backup, none of it on Google or cloud. Only a complete house fire will erase my backup.