Dell Latitude laptop doesn't boot 1st time, but does after forcing power off

As posted by another person - but it was never answered - every time I power on my Latitude 5400 after a full shut down, it gets stuck on the Dell logo. 

I can press and hold down the power button to force a power-down, and then it boots into Windows 11 as it should. 

Things I have tried:

- reset the bios/UEFI to defaults

- changed the boot order from "Use Windows Boot Manager" to "Use SSD" (or similar),

- disabled fast start-up in Windows Settings - Power plan - What the power button does

- disabled secure boot in Windows settings.

None of these have worked, and I am at a loss what to do.

The official Dell advice is to carry out the above bios step, then "remove the battery"... but I can't do that because the battery is sealed inside the laptop (grrrr!).  After that it's talking about a complete re-install of Windows, which seems a bit drastic (as I'm fairly sure it's a bios problem - the Dell splash screen is part of the pre-boot checks, surely, so nothing to do with Windows?).

There is also mention of a boot troubleshooter, which I haven't been able to find.

Is there any other solution? It's a complete wind-up each time the laptop starts up.

Apologies for re-posting an old problem, but so far I haven't found a working solution.