I think that the best way to start to look at this is for you to send an image of your Odin mode or Download mode screen. Often this is associated with some proprietary lock, this is usually revealed on the Odin mode screen as a certain lock or a variant of “Prenormal”. The text on this screen is quite small and hard to read.
More information (or clues at least !) in this article Know your hardware - Samsung.
I seem to recollect some issues with this model, revealed by a search Search results for 'Galaxy Tab S5e WiFi' - /e/ community and Samsung - Galaxy Tab S5e (Wi-Fi) - gts4lvwifi - Documentation Suggestions - #2 by trashHeap