Same here, and it is not an antivirus thing, NBminer disappeared from nicehash and I don't know the reason behind it and whether it is temporary or not.

I reinstalled Nicehash with the antivirus firewall and everything disabled from a brand new executable and from 2 older versions that I had and used in the past, but in all these attempts NBminer was not available and nowhere to be seen, it didn't even ask nor attempt to install it.

Nvidia's X50 or XX50 cards are known for not being good for mining or any heavy processing ( in heavy games, ML, ... ), take the GTX950, the GTX1050, the GTX1650 ...
They are budget options that are cheap and extremely weak compared to the higher end cards the XX60, XX70, XX80, XX90.

XX60ti cards are known for having good price/performance ratio, at least where I live. going lower to the XX50 is not a good choice. imagine an XX50 card plus LHR nerf, making the weak thing weaker. For these reasons I knew that the 3050 won't be useful for mining before it was released, and before knowing its specs.

One more thing XX50 cards are known to be cheap, and when reselling it you'll sell it only for a fraction of its brand new price (at least this is the case where I live).

Not good at mining + It doesn't retain its value like higher end cards = one of the worst deals