Salve weero,
apology for not searching: If my memory holds me, at the end of every year M+ offers a fast track to 1K: For paying a (small) fee you don’t need 100K EQM. Maybe this is cheaper than to buy booking class B and up. But please check with the experts!
As a 1K you earn at least six confirmed SWUs good to upgrade from booking class W (??) and you earn 200% award miles. IMO perfect as long as it last!
For everyone who is travelling on a tighter budget IMO it’s not a bad deal to buy the cheapest upgradable coach fare and upgrade either by SWU (if you ran out by miles) or “operational”. I hope in that way you save some money for buying some dirty cheap Biz tickets like SYD-BKK-FRA-MUC-LAX-SYD (2 times/year and your SEN status should be covered).
All the best!!