How would I fix these cylinders?

[Michaelaisascardydog]

Theres no cylinder corner piece.

[99guineafowl]

Perhaps try using a sphere to fill the gap. It’s kind of like an alternative cylinder corner piece. Hope this helped.

Edit: Here’s an example of sphere corner pieces:

[AlphaSeasprite]

For a “cylinder corner piece”, use a sphere.

This video sums up how to do it well.

[Scottifly]

Or if you want to get into Unions make a Negative Part at 45 degrees right at the corner, then do the opposite on the other cylinder Part.
Try aligning your Parts a bit better before you do it though, otherwise your edges are going to be pretty obvious.

[Yivex]

You may use a sphere, or you could play with negate and ctrl + d to even it out.

[Michaelaisascardydog]

Yeah I tried that and it looked weird at first but your example helped me, thanks!