I've got at least one box where I find it very hard to get into BIOS/Setup mode.... the easiest way for me for some is just grabbing a recent Ubuntu ISO/ thumb-drive & boot that, as some give me a enter-BIOS option.
Note: my issue is likely that I've a number of boxes, and thus at least six different ways that are needed to be used to achieve it, and for non HP/dell/lenovo boxes the methods vary quite & a bit considering I don't need it very often... eg. one requires me to hold down a specific key whilst the box is off; after a few seconds it'll turn on & ask what I want to do
Also note: I mention Ubuntu ISO, where I'm referring to main Ubuntu Desktop, or flavor such as Ubuntu-MATE; most of my recent thumb-drives will be QA dailies (ie. unreleased products), and in most cases all for the same release offer the same options on the same hardware, but it varies on ISO/release.
eg. I grabbed my Ubuntu-MATE thumb-drive (looking at the chart for which it is, thumb-drive 2, hunt for it), grab a sony vaio thingy I have & boot it... The 7th item on the GRUB menu is "UEFI Firmware Settings", selecting that puts me in VAIO Care (Rescue Mode).
Sorry: I didn't look at what release/daily was on the thumb-drive; I can see the last I downloaded was lunar but I suspect I had another release on the thumb-drive.