The core of the server on which Spigot is based, produces similar errors:
Can't keep up! Is the server overloaded? Runing 5005ms or 100 ticks behind
Minecraft JE 1.14 is not too optimized.
Command /timings from Spigot core:
https://www.spigotmc.org/go/timings?url=zusawugime

The core is unstable in functions:
0.69% 4,182.85% 16.73 s 2,091.42 ms 0.0 0.0k World Save
33.23% 34.47% 807.35 s 17.24 ms 1.0 46.8k world - doTick
28.31% 29.37% 687.77 s 14.68 ms 1.0 46.8k world - tickEntities
37.80% 39.22% 918.40 s 19.61 ms 1.0 46.8k Full Server Tick
28.53% 29.60% 693.14 s 14.80 ms 806 37,769.3k tickEntity
28.07% 29.12% 681.90 s 14.56 ms 1.0 46.8k world - entityTick
23.50% 24.38% 571.08 s 12.19 ms 132 6,173.9k Activated Entities