I run a modded server. I have a regular pop of 40-50+, but about 70-100+ players on busy hours. On server start, I get about normal CPU usage of 40-50%, stable. I noticed when server gets busy, about 70-80+ players, the CPU usage spikes to about 185-200% continously, which is ok because my hosting limits it to 800% but latency spikes and rubberbanding ingame can be noticed randomly. I'm not sure what may be causing it. I'll post my plugins below. Any kind of response/help is appreciated.

01 "AdminHammer" (1.13.0) by mvrb (0.00s) - AdminHammer.cs
02 "AdminMenu" (0.1.50) by k1lly0u (0.07s) - AdminMenu.cs
03 "Admin Panel" (1.4.7) by nivex (0.03s) - AdminPanel.cs
04 "Admin Radar" (5.1.9) by nivex (0.87s) - AdminRadar.cs
05 "AlphaLoot" (3.1.19) by k1lly0u (0.82s) - AlphaLoot.cs
06 "Better Chat" (5.2.12) by LaserHydra (0.02s) - BetterChat.cs
07 "Better Say" (3.0.1) by LaserHydra (0.01s) - BetterSay.cs
08 "Bypass Queue" (1.0.4) by Orange (0.00s) - BypassQueue.cs
09 "Clans" (3.0.27) by k1lly0u (0.04s) - Clans.cs
10 "Coloured Chat" (2.2.7) by collect_vood (0.01s) - ColouredChat.cs
11 "Crafting Controller" (3.2.7) by Whispers88 (0.04s) - CraftingController.cs
12 "Discord Wipe" (2.3.1) by MJSU (0.00s) - DiscordWipe.cs
13 "Gather Manager" (2.2.78) by Mughisi (0.21s) - GatherManager.cs
14 "Image Library" (2.0.60) by Absolut & K1lly0u (0.03s) - ImageLibrary.cs
15 "Inventory Cleaner" (2.1.1) by Joao Pster (0.00s) - InventoryCleaner.cs
16 "Inventory Viewer" (4.0.5) by Whispers88 (0.00s) - InventoryViewer.cs
17 "Kits" (4.4.0) by k1lly0u (0.02s) - Kits.cs
18 "Monuments Recycler" (0.2.6) by Dana (0.05s) - MonumentsRecycler.cs
19 "No Give Notices" (0.3.0) by Wulf (0.00s) - NoGiveNotices.cs
20 "PermissionsManager" (2.0.7) by Steenamaroo (0.03s) - PermissionsManager.cs
21 "Placeholder API" (2.2.1) by misticos (0.01s) - PlaceholderAPI.cs
22 "Play Time Rewards" (1.2.2) by Khan (0.03s) - PlayTimeRewards.cs
23 "PlayerAdministration" (1.6.8) by ThibmoRozier (0.00s) - PlayerAdministration.cs
24 "Quick Smelt" (5.1.5) by misticos (0.58s) - QuickSmelt.cs
25 "Quick Sort" (1.8.0) by MON@H (0.03s) - QuickSort.cs
26 "Recycle Manager" (2.0.0) by WhiteThunder (0.02s) - RecycleManager.cs
27 "Rust Admin" (1.0.1) by misticos (0.00s) - RustAdmin.cs
28 "Rust Map Api" (1.3.2) by MJSU (0.00s) - RustMapApi.cs
29 "Server Rewards" (0.4.74) by k1lly0u (0.30s) - ServerRewards.cs
30 "Sign Artist" (1.4.0) by Whispers88 (0.00s) - SignArtist.cs
31 "SkinBox" (2.1.20) by k1lly0u (0.25s) - SkinBox.cs
32 "Stack Size Controller" (4.1.1) by AnExiledDev (0.87s) - StackSizeController.cs
33 "Teleport Marker" (1.0.6) by Talha (0.00s) - TeleportMarker.cs
34 "TimeOfDay" (2.3.4) by FuJiCuRa (0.00s) - TimeOfDay.cs
35 "Timed Permissions" (1.6.0) by LaserHydra (0.00s) - TimedPermissions.cs
36 "Tipster" (1.4.8) by FuJiCuRa (0.04s) - Tipster.cs
37 "Vanish" (1.6.8) by Whispers88 (0.01s) - Vanish.cs
38 "Wipe Block" (1.0.6) by Mevent (0.27s) - WipeBlock.cs

what CPU , and how much ram.

Merged post

if it's shared hosting it's completely normal most shared hosts can only realistically support 40-50 max especially if it's modded and if you have a custom map that will also cause issues (completely depending on how optimized it is) but basically long story short the more entities you have the more lag you have. that's why it's recommended for dedicated hosting if you're going to take it serious and run a real community shared hosting is only really good for starting a community.