Hi I am a OW veteran and making my first *A trip next month and would like to know the best programme to join? The return trip as follows

Business

BNE - BKK TK operated by Thai Airways
BKK - IST TK
IST - TLV TK
TLV - IST TK
IST - BKK TK
BKK - BNE TK operated by Thai Airways

By my calcs there are 47670 points to be earned, I am of the understanding A3 is 4000 plus 16000 to Gold so it seems obvious to join, but is gold membership on other carries also possible and are their benefits better?

Welcome your input thank-you