Server reboots are meant to clear lag on the server every six hours. The few that do cause lag is most likely due to the fact that each server has to reload completely, so that many chunks loading in rapidly at once always has the possibility to cause a slow down (that plus all the players online.) If there’s still lag that everyone is experiencing as a whole in the server you’re playing on, it’s best to let a higher member of staff know if the issue doesn’t resolve by itself.
The server recently had a HUGE reboot and all plots were lost and claims etc. The server is technically new. There are a MASSIVE amount of bugs that need to be fixed every once in a while. Thus making the server reboot and adapt to the new bug fixes. All you need to do is be patient and wait until a lot of the bugs are fixed and there will be less reboots. (This may not be the case but is the most likley senario)