March 2023 is still a ways away so it’ll be a few months yet before you can even start to check award availability.
Departing and arriving back at Sydney will give you the best chance at finding seats.
Looking at flights that are flying right now, Etihad seems to be the best option given your large stash of Velocity points. Your stash should be enough for two return in business, but of course do check with the new award charts and all.
I would advise against transferring your St George points right now given the uncertainty still with award availability and who knows what else might happen between the UAE and Israel. Best not to keep your eggs all in one basket and just transfer when the time comes, if you need it.
For your KF miles, they aren’t going to do you much good if you are looking for 1 stop itinerary. And even transferring your points in from St George, it’s not going to be nearly enough for business flights. I would think to save this for another time.
Just my two cents.
Singapore and ANA don’t offer one-stop to Tel Aviv right now. Etihad really seems like your only option atm.
If you are looking to do a bit of First Class, Etihad is going to be a lot easier to get award seats than Singapore airlines (who rarely release them to partners, especially their coveted suites).
You might consider one-way taking Etihad First and one way having a stop over in Singapore.
Keep in mind that you need Krisflyer miles to use this perk of having stop overs. You’ll likely need to transfer some Velocity points over to Krisflyer. This means taking hit at your balance so you’ll have to decide whether its worth it to have a stopover by redeeming with Krisflyer.
First class on etihad with Velocity isn’t too hard. Plenty of people have done that before.
First class on Singapore Airlines? I would forget using Velocity points directly for that. I think I’ve seen first class space released once or twice and they were always on their old 777 seat which really isn’t that great when you’ve seen the A380 suites.
The only realistic chance you’ll get at flying Singapore first is transfering to KF. If you are doing that, I’d recommend flying out of Singapore for that because the experience is far superior there than at say, Sydney. Also, keep in mind then that you’ll probably have to make that a two stop itinerary costing you more points as well so you’ve got to factor that in!