First of all Sigma 5 is not even a virus or something similar

There are two answer for this:

The first one is that SIGMA 5 is not a BTC or Monero miner, there are some proof posted in the original reddit of Sigma, saying why all accusations doesn't make any sense , explaining how Sigma 5 works and why it runs so slow.

The second one is yes, Sigma 5 is a BTC or Monero miner, some pleople already deobfuscated the client and finded some sus thing and should not be there, explaining the port 3000

But that doesn't matter a this point because the miner is only executed meanwhile you are using client, so if you close the client, the miner stops and isn't working, so if Sigma 5 has a BTC or Monero miner, its safe and its not gonna destroy your pc or some thing