ive always used this style of belt covers on my ender 5 from when i first got it an after a couple of years of running it i started experiencing layer shifts an my first thought was it was due to the belts cause i had never replaced them or tightened them so i went to the belt tensioner i was most familiar with for my ender 3 printers for the x axis an it worked with the ender 5 x axis also but not with the belt covers so i took an modified it so it would accept the printable tensioners for sure but not 100% sure about the metal ones that u can purchase, it might work since they look to be more compact than the printed ones i use. i hope someone else finds these useful. the original that i used to remix to make this is from these 2 links.
https://www.thingiverse.com/thing:3465579
https://www.thingiverse.com/thing:3412007
my ender 5 was my first printers is over 3 yrs old at this point an i know theres been updates and newer versions out now so i dont know what all has changed from mine to whats out now but this should work. if not the originals have been remixed alot so there is alot of other versions but ive not seen any others that make clearance for a tensioner so if what i have made doesn't work but u find one that does fit ur machine let me know an i can do the same to it an i'll update it with newer versions but i only have the older machine to test it on so can only confirm it works on them but from what i can tell just from looking at them in pictures nothing has changed that would effect it so hopefully it works on all of them.