Single player lag of mobs and block placement/breaking after updating old world

After updating a world created prior to the aquatic update I experienced some notable lag in manipulation of blocks and all mobs despite the game running smoothly otherwise. Additional lag was noticed by an extended eating effect that would run up to 5 or 6 seconds and extended sleep animation; whereupon I noticed that the setting sun would occasionally update to several seconds earlier in the day and slowly worked its way below the horizon. I searched for options and fixes online to now avail. I optimized my world in the current 1.15.2 edition whereupon the performance dropped significantly.