It is likely Vietnam will buy some. But until it enters mass production and the Izd. 30 gets into service I doubt it will get any exports.
As is the Russians cannot even produce enough for their own use.
The Russians are still working on putting the Su-30SM2 into mass production. If they were that gung ho on the Su-57 they would not be doing this. They are not going to cut Su-35 production either. Both aircraft compete with it on the engine resource for example.
We still don't know if they can produce the AESA radar in quantity either.
When they cut Su-35 production to focus on the Su-57 then it will be the sign this aircraft has enough production for export I think.
Vietnam would go for Su-35 before they even consider the Su-57, which needs to serve as a mature platform in RUAF for some time first. The Vietnamese armed forces are also notoriously stingy when it comes to arms acquisition. When they purchased the MKK/MK2 they didn't include very many add-ons that China/Indonesia selected.
Russia’s Su-57 fifth-generation fighter capable of carrying four attack drones
The fighter designated to destroy all types of air, ground, and naval targets
Sukhoi Su-57 fighter jet and Okhotnik heavy strike drone
MOSCOW, June 1. /TASS/. A pilot of the Sukhoi Su-57 fifth-generation fighter jet will simultaneously coordinate the operations of four latest Okhotnik heavy strike drones, a source in the domestic aircraft-building industry told TASS on Tuesday.
"Currently, the options of controlling strike drones from a Su-57 cockpit are being worked out. A fighter jet is expected to carry from two to four Okhotnik drones," the source said.
TASS has no official confirmation of this information yet.
As the press office of Russia’s United Aircraft Corporation (UAC) earlier told TASS, the latest Okhotnik drone will strike aerial and ground targets in network-centric interaction with a Su-57 fighter. In their joint employment with the fifth-generation fighter, Okhotnik drones will deal with a full range of tasks, striking aerial and ground targets under the command of a Su-57’s pilot.
The Russian Armed Forces received the first Su-57 fighter in 2020.
The S-70 ‘Okhotnik’ developed by the Sukhoi Design Bureau features stealth technology and the flying wing design (it lacks the tail), which reduces its radar signature. According to the data of open sources, the drone has a take-off weight of 20 tonnes and can develop a speed of around 1,000 km/h.
The Okhotnik heavy attack drone performed its debut flight on August 3, 2019. The flight lasted over 20 minutes under an operator’s control. On September 27, 2019, the Okhotnik performed a flight together with a Su-57 fifth-generation fighter jet. The drone maneuvered in the air in the automated mode at an altitude of around 1,600 meters, and its flight lasted over 30 minutes.
The serial deliveries of Okhotnik heavy strike drones to the Russian troops are scheduled to begin from 2024.