If I remember correctly the Italy/Austria/Vietnam/Nepal info was different than the South American info. The producers had a backup of legs in South America and intended on using them if necessary if things got worse with the pandemic during the filming of TAR33.
Yeah this was my recollection as well, it wasn't particularly clear when using South America came into the mix but it also wasn't on the original route. It sounded like a last ditch attempt to finish the season off in a somewhat remote fashion.
Also after a heavy season of South America in 35, I'm thinking we will give it a big miss this time around.
The thing to keep in mind is that 33 was scheduled to film in Feb/March 2020, 36 is slated to film from now until July. With different timings of year/climates, what they originally had planned for 33 may not necessarily fit in with 36's schedule.