Launching a missile on a server causes a massive frame drop until it hits its target. I don't know much info as to WHY, but all I know is that the debug pie maxes out 'gametick' when I launch the missile.

Which server core are you using? Or are you just opening your world to LAN and play thru Radmin VPN \ Hamachi etc. ?
Mod list?
Computer specs? (cpu \ gpu \ memory)
Optifine? Shaders?
IF you have optifine, do you try to remove it \ reset settings?
Any optimisation mods like Foam fix and etc? Do you try ro remove them?
Is your VGA driver is up to date?

Please, leave more info. And you are sure it's HBM fault? Do you test it with HBM installed only?

I'm using the Exaroton provider. I've tested the mod alone and with a modpack, and both ways the issue persists. And yes my graphics card driver is up to date. How would I get the info? I cant seem to find a log anywhere that logs the issue itself.

It's likely the game is processing the flight of the missile and the resulting explosion which varies depending on what you do this is completely normal or could mean you need to allocate more ram

I have 8 gb of RAM allocated to the server. It lags even when the target is 20 blocks away

I have the same problem. Did you fix it?