Hold shift and double click the event, it will select all events after.
I have known this for a long while, but to double check if it was hard to figure out on your own I googled “cubase select all events” and it’s the second result. I also found it in the manual in 40 seconds using “ctrl F” to search in that section of the PDF.
Try to put a few minutes of research into how cubase works before requesting features or the actual improvements that could be made to the software will be lost amidst the wash of people asking for a features that already exist.