Trainer aircraft progression: What is ideal?

Swiss
Simulator -> pc-7/9 -> pc-21 -> FA-18D or F-5B?

Israel
Simulator -> Grob-> Texan -> M-346 -> F16B or F-15B?

Singapore

Simulator -> Pc-21 -> M-346 -> F-5T?

Saudi
Simulator -> Pc-21 for all until 2 seat converter

there’s a lot of options.. sometimes used differently. Singapore PC-21 is considered basic while in Swiss it seems more advanced (correct me if this is wrong)