TBH I don't remember seeing "combined delivery" offers anywhere in 2023. I think this marking has been retired permanently.
Packages ordered at similar time with AliExpress Standard or Saver Shipping are still typically being combined. It simply saves AliExpress money, now that they actually need to pay their last mile carriers. I don't know the exact rules, but I have made a few orders from multiple sellers in 2023 and all of them were combined. They even combine orders from different baskets, if they are close enough in time.
AliExpress also introduced "Choice" offers. Items with "Choice" label always use combined delivery, you pay a flat rate for shipping regardless of which seller or sellers you order from and shipping is free on orders above $10. Supposedly this works by participating sellers storing their stock of "Choice" items in AliExpress' own warehouse together with others, which means that you will most likely see this option offered on popular, high volume products.