Easiest way to split notes to smaller rhythmic values?

[ShacharHarshuv]

Give a note / chord, what’s the easiest way to split it down to smaller rhythmic values? Preferably without needing to reinput the note.
For example, let’s say I start with this:

and I want to make this:

[Lillie_Harris]

Show the caret, position the caret at beat 4 on those staves, press U to cut.

[ShacharHarshuv]

Amazing! Thanks