Lazy DataFixerUpper(LazyDFU) [FORGE] is a Forge optimization mod for Minecraft 1.16.1 - 1.19.3, ported from tuxed’s Fabric mod. It speeds up startup by delaying DataFixerUpper migration rules until they are needed, without modifying DFU itself. Compiling those rules later can cause a temporary lag spike.
On your rented Minecraft server, install LazyDFU with one click from the panel to defer migration-rule compilation until it is actually needed.