Bowden Extruders are a system of feeding the printing Filament into the "hot end" the part that has the nozzle and melts the filament separated by a flexible plastic tube. The problem with this is with soft and flexible filaments they get squashed and stretched by the extruder pushing the filament down the tube and the resistance of the constriction of the nozzle putting the Extruder right on the top of the hot end solves that problem but does raise some other issues.

Bed leveling is a gimmick and allows manufactures to save on very flat print beds - its much cheaper to make bed leveler than to provide a thick flat build plate. The bed leveler allows the print head to move up and down to follow a wobbly bed. The first upgrade that most people make is to obtain a plate glass print bed. Because glass is naturally flat the bed leveler becomes redundant !! Once leveled even here where we change print bed plates almost daily we only level the bed each week or so taking perhaps 5 mins against which if you look at the cries for help on the forum you will see bed leveler are literally more trouble than they are worth.

The Creality brand gets a lot of Bashing on the forum but I have been using an Ender3 pro for the last 15 months with no problems but I might have been lucky meanwhile I have just ordered a Sapphire pro to replace the ender to get the graeter speed. I use the 3D printer to provide commercial prototypes for our science and design consultancy.

Finally the Sapphire Pro uses different method of moving the print head and build plate which enables it to print at a greater speed.