Which desktop environment will let me jump to the next file with the same first letter in filename, when I press a key few times with delay [duplicate]

Solution 1:

I tried a few file managers in a VM and Konqueror seems to meet your needs in that particular instance. Install with sudo apt install konqueror. You might want to switch to e.g. Kubuntu for good though, because it needs all the KDE dependencies, and it looks out of place in GNOME, but since you were asking for a desktop environment anyway that might not be a problem for you.

I found this relevant piece of information in the docs

Select a file or folder by typing the first few letters of its name and the first matching item is selected. To clear the selection and cancel the keyboard search press Esc or wait longer than the timeout of 1 second.

(emphasis mine)

I did find, however, that you don't need to wait if it's unambiguous.

Solution 2:

Caja file-manager (from caja package) provides this functionality - see screencast below:

Note: Esc is really not needed, you can wait for timeout to be reached.

Also you maybe interest in removing GNOMEs Hell and installing whole traditional and cool MATE Desktop environment instead. See this Q&A for details.