I don't play 5e, I haven't even looked at it, yet. I've creating and publishing Starfinder content, so my focus has been there, and had no need to look at 5e. That said, a project I shelved about 6 years, but do want to make a return perhaps next year is a Weird West setting and adventure series, that would probably be more ideal to be published as 5e/PF 2.0, and then I'll look for the first time. Is there even a gun mechanic in 5e?
Depending on the 5e gun rules, if such exist, the setting I'd be building would be designed for 19th century technology, so cap and ball or cartridge ammunition would be standard technology accessible to everyone. So guns wouldn't necessarily have to be balanced with existing D&D weapons technology, and perhaps designed more true.
The Weird West setting is actually based on 19th Century Earth, and would presumably best fit as humanocentric, because of that. It's a not an Old West flavored fantasy setting, rather real Earth with magic built in. I can imagine an NPC Wyatt Earp, Samuel Clemens or Marie Laveau possibly appearing in a module. I'm combining real world Earth history with Templar/Masonic conspiracy theory, and cosmic/gothic horror elements as a setting concept.
I'm wondering if developing powerful gun rules, than the expected balance with existing weapons used in a setting where everyone has access to guns as viable. But considering knives, swords and bow and arrows still have a place in the game of course, so more balanced would probably be better design tact... thoughts?
As an aside, in typical medieval flavored games I avoid guns in my game, but in a setting where guns are the expectation, I'd go heavy that way.