How a boot loop prevents access to TWRP? I found an old Samsung Note 4 of mine which I flashed a few years ago (Lineage OS if memory serves me right) and which I wanted to reuse for my son.

It is unfortunately stuck in a boot loop:


If booted normally, it goes though the "Samsung Galaxy Note 4" initial screen (black and white and then after some time there is a vibration and it reboots (in a loop)
If booted with HomePowerVolume-Up, a blue `RECOVERY BOOTING...." appears together with the Samsung Note 4 screen above, then it reboots (in a loop)
If booted with HomePowerVolume-Down it goes into Download Mode


I tried to flashed the latest TWRP  (3.2.3) via Odin - no changes

What is the reason of such a boot loop? Is there a bootloader missing? (I found a bootlader and flashed it, the flash was successful but the problem is still the same)

My main goal is to boot into TWRP in order to wipe and reinstall a new Lineage OS

Note: Following up on the comments and answer, I wanted to clarify a few things:


the Note worked fine with Lineage OS installed
it was then left aside
it was then (not sure here) probably wiped via TWRP (the only thing sure is that at most the wipe functionality of TWRP was used, to do a factory reset). This is new information obtained after the one who had the phone in hands told exactly what she has done.
and then the problems started


This is to make it clear that it used to have a functional TWRP and a functional Lineage OS, then a wipe in TWRP occured, and then it cannot boot to TWRP (or Lineage)
A boot loop can be caused by several reasons.
• Incompatible Boot and Recovery Image's.
• System Modifications
• File Permission Errors
• File Owner Errors
• Incorrect Formatting Of Files
• Knox 
And the last one i can think of is incorrect settings ( build.prop edits etc.. )   

Yours seems to be the first one, or the last, Incompatible Recovery and Knox

Obviously you have had a working TWRP on that device before, so maybe you still have it from flashing the device years ago. 
Custom firmware like Lineage OS can also require it's own recovery image, that is dependent on the corresponding Kernel version.  

If your Lineage OS installation was for an UPGRADED Android version like 4.4 to 5.1, then a new kernel for 5.1 will have overwritten your 4.4 kernel, and now that possible working TWRP is useless... This became a huge problem with people trying to downgrade device's, as it requires a factory level flash. Odin may have the ability the downgrade the devices boot image ( kernel ). and TWRP will work again, but Knox will stay triggered.