Looking for new EF lens for photos of people and groups

[sequoialondon]

Looking for new lens for Canon rebel t7

For work, I take a lot of photos of people and group photos at events, and I am not happy with the grain-like texture that shows up in my photos. I'm shooting in raw, I'm editing on Photoshop, I go in and de-noise it both manually and automatically, but it never looks as sharp as I wanted it to. I want to better my craft, so I was wondering if anyone had any suggestions as to a different lens for event photography while still keeping my DSLR. Or if there's any suggestions as to which camera would be better, while trying to stay relatively on the cheaper side, that would be great. 

Thank you in advance! 

[sequoialondon]

Sure thing, thank you for taking the time to respond. Here's an example of one that I took. I shoot in RAW, when it prompts me to open a CR2 file, I'll edit in that. I usually don't de-noise it more than 20 on the sliding scale. I'll hit auto and then de-noise it and that's it. I'm not a huge expert on photoshop, but I can tinker my way around it.  https://www.facebook.com/photo/?fbid=998326082330801&set=pb.100064602557367.-2207520000 

https://www.facebook.com/photo.php?fbid=1001174468712629&set=pb.100064602557367.-2207520000&type=3

https://www.facebook.com/photo.php?fbid=970468501783226&set=pb.100064602557367.-2207520000&type=3

I always feel like the center of the photos are in focus but not the outside. 

[normadel]

I could not view your samples because I am not a Facebook user.

Your 18-55 is just fine for what you want.

What exposure mode do you use....Program, Aperture priority, Shutter priority, Basic Zones, what?

A lens doesn't cause or contribute to "graininess". What CAN is very high ISO setting, perhaps caused by using Auto ISO and there not being enough illumination.

Look to your technique before looking for equipment cures.