Originally Posted by RealHJ

DL will probably give you only routing via SYD (DL+VA), that will be obscenely priced with additive pricing and the crazy-high DL award prices.

Try to avoid having any DL flights in the mix to get a bit of a reprieve (may be...not sure) from all the massive "enhancements" (i.e., major devaluations) of the last several years. Search for individual segments of logical routings (via TPE is good, also TYO, KIX, ICN, PVG, etc. - of course this all presumes that by sometime next year all those countries will be opened up, which is still a big if), see what's available, then you can try to call and get an agent to piece it together, but expect heavy resistance and numerous HUACAs. As a rule it takes about as much time to book a flight using DL miles as is the flying time; if anything now it's even more so. So, expect to spend some 10s of hours on the phone over several weeks to get a valid routing booking at a through fare...and it's far from certain that you'll be able to get it, as now "there are no rules," so DL can do whatever it wants. Your best bet is to get a more experienced agent with access to the command-line reservation system (you can try asking for Global Ticketing Support), who may be able to book you through that - how it "used to be." If anyone still has that access nowadays (not sure).

Also look at alternate origin airports (e.g. YYZ, ORD, WAS, etc. - then get a separate connecting flight to there) and destination airports (CGK, SIN, KUL). Often that's the only way to get a J class award, and then buy the connecting short-haul flight(s), on one or both ends.