I would like to know which companies
would you recommend for an engineer with 2 years experience in embedded systems(STM32) as well as PCB design (Altium)
Uhm, depend what you are looking for; at some time you will probably need to decide whether you want to specialize in hardware design or embedded systems design and programming. Good news there are lots of options, over the years whether due to retrenchments, bankruptcy or just the need to move on I always had the opportunity for dozens of interview and 3 to 5 offers within a month
SA Companies that tend to be safe from country's economy:
Asset tracking companies Tracker, Mix Telematics, Altech Netstar, Cartrack
Military and Aerospace: Couple of satellite companies around Stellenbosch, Ruetech Radar, Milkor
In the retail and fintech space that focus on the informal market: Kazang and Yoco
Then are niche options as well Canonical have enigneers that assist companies designing Ubuntu based IOT devices and small dev houses.
Then there are lots US and EU companies that do their development in South Africa, either in their offices in Cape Town or Gauteng but remote is always an option. They usually want the best but also pay the best due to the normally favouring R/$ exchange.
So then OP really needs to apply there.
He can actually go work for them, Altech UAC (Durban based IIRC) was the company that did the work, they now design & manufacture premium dish, decoders, IP box systems for EU and Australian market. MC will probably continue using cheap chinese crap well trying to sell themselves as the last bastion and champion of the South African economy and jobs.