Lag:
If players are teleporting around maybe say, four blocks at a time, then that means your internet is experiencing Lag. Lag is also known as 'ping', ping is the time that is takes for your internet to reach the game and/or application.
The most common reason for lag is multiple devices connected to one internet modem. If you are experiencing this, that means your ping is usually 350 plus.
Something you can do to reduce ping, is checking if any downloads are happening in your household, and if there is then try pausing them until you are done what you are doing. Another thing is closing all your tabs or applications on your device, because there could be multiple tabs trying to access a website on your internet application.
FPS (Frames Per Second)
FPS is how smooth your device is running on a game or an app. The most common causes for Frame Drops is your devices age, or software implemented in it. The unfortunate truth is what
@ComplexSanta stated, which is your device maybe 'out-of-date'.
I am not suggesting that you pay more money for a better device, but if you are trying to play minigames such as Skywars, you may want to die down on that, because skywars has a lot of skill needed to play it well. To be skillful at skywars you need to be able to turn your character around smoothly. This is crucial when playing a game like skywars, which is extremely hard to be good at without a device that runs 45 FPS+.
What I would suggest is playing a game like murder mystery. The main reason being is that you don't have to be good at Minecraft to play it, just simply find a decent hiding spot and wait for the game to end.
*Some of the information in this comment may not be correct*
