fastboot is not usefull on Samsung device :
but adb devices must return something, are you sure of your cable ? USB port ?
On linux, you have to use Heimdall(CLI), Odin4(CLI), Galaxy-Flasher(GUI) or Eros(android OTG)
not so old from my point of view…
but that look very old to me,
Download Galaxy Tab A (8.0 inches, 2019, Wi-Fi) SM-T290 (PHN) T290XXS3ATF1 in Samfw - Samsung firmware download
Android 9 (SECURITY PATCH LEVEL 2020-06-01)
latest version is
Download Galaxy Tab A (8.0 inches, 2019, Wi-Fi) SM-T290 (PHN) T290XXS5CWG5 in Samfw - Samsung firmware download
Android 11 (SECURITY PATCH LEVEL 2023-05-01)
better is to use Galaxy-Flasher for upgrading stock firmware, then Heimdall to flash a custom recovery.