Hi, and welcome to the Apple Community.
We are all Apple users, like yourself, in this community, so have no way to change that holding period.
Seems the clipboard is mainly for immediate copy and paste tasks, leaving it free to use over and over for various tasks.
(For myself, I keep a "daily" text file on the desktop, and may save clipboard text / images there until needed.)
Looked into the new "Universal Clipboard" but seems it is the same story there.
Apple's article:
Use Universal Clipboard to copy and paste between your Apple devices - Apple Support
Says:
"It remains there briefly, or until you replace it by copying something else on either device."
I could be wrong, but there don't seem to be any upcoming changes to the length of time clipboard holds text.
Apple welcomes feedback on its products and services.
If enough people send feedback on an issue, it may help effect change.
(Don't expect an answer though.)
Here's a link to the feedback webpage:
Product Feedback - Apple
All the best :-)