[Samsung Galaxy Tab S6 Lite ROMs, Kernels, Recoveri] eleWator:
Step 5. The device will demand you format userdata, please follow the onscreen instructions to do so.

This never happens for me on my SMP-615 (2022 edition).

Also facing problems with heimdall on linux,

ERROR: Failed to send handshake!ERROR: Protocol initialisation failed!

Will try to find a older machine that is pre USB3 ports or something and try again, maybe someone knows whats happening or has any further ideas?

some debug

heimdall print-pit --verbose --no-reboot
Heimdall v1.4.2

Copyright (c) 2010-2017 Benjamin Dobell, Glass Echidna
http://www.glassechidna.com.au/

This software is provided free of charge. Copying and redistribution is
encouraged.

If you appreciate this software and you would like to support future
development please consider donating:
http://www.glassechidna.com.au/donate/

Initialising connection...
Detecting device...
Manufacturer: "Samsung"
Product: "SM6150"

length: 18
device class: 2
S/N: 0
VID:PID: 04E8:685D
bcdDevice: 021B
iMan:iProd:iSer: 1:2:0
nb confs: 1

interface[0].altsetting[0]: num endpoints = 1
Class.SubClass.Protocol: 02.02.01
endpoint[0].address: 82
max packet size: 0010
polling interval: 09

interface[1].altsetting[0]: num endpoints = 2
Class.SubClass.Protocol: 0A.00.00
endpoint[0].address: 01
max packet size: 0200
polling interval: 00
endpoint[1].address: 81
max packet size: 0200
polling interval: 00
Claiming interface...
Setting up interface...

Initialising protocol...
ERROR: libusb error -7 whilst sending bulk transfer. Retrying...
ERROR: libusb error -7 whilst sending bulk transfer. Retrying...

heimdall detect --verbose --usb-log-level debug
[timestamp] [threadID] facility level [function call] <message>
--------------------------------------------------------------------------------
[ 0.004329] [003898fe] libusb: debug [libusb_get_device_list]
[ 0.004337] [003898fe] libusb: debug [libusb_get_device_descriptor]
[ 0.004340] [003898fe] libusb: debug [libusb_get_device_descriptor]
[ 0.004341] [003898fe] libusb: debug [libusb_get_device_descriptor]
[ 0.004343] [003898fe] libusb: debug [libusb_get_device_descriptor]
[ 0.004345] [003898fe] libusb: debug [libusb_get_device_descriptor]
Device detected
[ 0.004351] [003898fe] libusb: debug [libusb_exit]
[ 0.004368] [003898ff] libusb: debug [linux_udev_event_thread_main] udev event thread exiting
[ 0.004418] [003898fe] libusb: debug [libusb_unref_device] destroy device 6.1
[ 0.004422] [003898fe] libusb: debug [libusb_unref_device] destroy device 5.2
[ 0.004423] [003898fe] libusb: debug [libusb_unref_device] destroy device 5.1
[ 0.004425] [003898fe] libusb: debug [libusb_unref_device] destroy device 4.1
[ 0.004428] [003898fe] libusb: debug [libusb_unref_device] destroy device 3.49
[ 0.004431] [003898fe] libusb: debug [libusb_unref_device] destroy device 3.3
[ 0.004432] [003898fe] libusb: debug [libusb_unref_device] destroy device 3.2
[ 0.004435] [003898fe] libusb: debug [libusb_unref_device] destroy device 3.1
[ 0.004438] [003898fe] libusb: debug [libusb_unref_device] destroy device 2.1
[ 0.004440] [003898fe] libusb: debug [libusb_unref_device] destroy device 1.11
[ 0.004442] [003898fe] libusb: debug [libusb_unref_device] destroy device 1.2
[ 0.004445] [003898fe] libusb: debug [libusb_unref_device] destroy device 1.1
[ 0.004447] [003898fe] libusb: debug [usbi_remove_event_source] remove fd 4
[ 0.004451] [003898fe] libusb: debug [usbi_remove_event_source] remove fd 3