How to account for ping spikes? (Server/Client)

Hi, this is a more general question about how we can use Lua or the tools of Roblox to deal with ping spikes. Anytime I try to implement a sort of weapon with projectiles, any lag spike I get makes the projectiles freeze momentarily. I just tried out the FastCast example gun on a default Baseplate to narrow it down, and I know that the projectile freezing corresponds to my ping spikes. (Gun: https://www.roblox.com/library/4453914752/FastCast-Redux-Example-Gun).

Now, I've played games where I never feel like I'm lagging, even if my ping may be high or my ping spikes. Is there a technique to accomplish this that I haven't discovered? A game setting, or something to do with how they code their projectiles?

I mention the Fastcast gun on an empty baseplate because I feel I shouldn't be running into this issue with ping spikes just with something simple like this; I know Fastcast is often recommended as an API for handling projectiles so I'm sure there's something that developers so that it feels smooth even with ping spikes. Any help is appreciated!