> I use a cheap dynamic mic from ebay with a windscreen and a mic arm and it sounds fine.

How do you know what it sounds like?

How do you know how good you sound to other people compared to if you were speaking through a good condenser mic?

Open voice recorder, record, say things, listen.

Plus multiple services now offer test calls/contacts where you can open a voice call, say things, and then listen back to how the other side hears it.

Put on headphones, linked to your phone, mute the phone mic (do not skip this step), and hold a video call with yourself between your computer and your phone.

Make your own zoom call and record it...

Quality supercardioid microphone will reject echo well enough for most rooms and a meter or two distance. That is usually enough distance to not typically require a pop filter, this giving improved clarity.

Hypercardioid "shotgun" works too as long as its back is placed far enough off a wall, however these tend to have sound coloration.

It just so happens that most microphones are the less directional cardioid. Or worse, omnidirectional.