Boot mode: Ignore legacy?

[ChrisGreaves]

I am used to choosing the boot media sequence from BIOS days.

Bonavista_20200712_111942.JPG

This extremely poor photo of my Acer TravelamateP2 screen (after interrupting the boot with the <F2> key) shows my limited options.
Basically: I am given no choice. I can't change anything on the screen. From my current point of view they could have made this screen read-only, disabled.

I have read Win10 posts and understand that BIOS is on the way out, and that UEFI is on the way in. I seek confirmation on the following statements
(1) If in doubt, from now on (this Acer and all future machines) use UEFI, but use Legacy only as a last resort.
(2) What I used to do in BIOS, especially boot sequence, will now be done through Windows prior to rebooting and making use of the new boot order settings
(3) Assuming that I will (in a few minutes) be able to choose from HDD, CD, USB disk drive, USB memory key, this suggests that if I don't fix this boot order stuff early on, I could find myself with a boot/recovery/system media that I can't use because I didn't change this boot sequence soon enough, that is, while Win10 was running.
(4) The third point is the critical difference from [the good old days] when I could at least get into BIOS and tell the machine to look at the CD drive (or whatever).
Thanks
Chris
P.S. If you are wondering why I am only now getting around to boot sequence after 2? 3? weeks, it is because I have been cursed with a series of days which are absolutely ideal for digging beds, composting, moving the hose every hour, and eating lunch under the trees with the birds chirping away.
C