There was a recent post on this site,
Keys for Entering BIOS/UEFI by Computer Manufacturer and Model, that list the keys to enter UEFI or BIOS by manufacturer and hardware style. F12 does not appear to be one used by Asus.
As a side note, if your machine has UEFI now, it has always had UEFI. You don't and can't zig-zag between true old-style BIOS and UEFI, and all BIOS functions are subsumed under UEFI on any machine produced from right around the time of the introduction of Windows 8 and onward.
There is always a way to change to boot order to suit yourself, whether as a one-shot or permanently. As
@SleepyDude has noted, you may need to turn Secure Boot off and, possibly, enable legacy boot mode.
This isn't something that Acronis did, unless when you installed it you had it set itself up such that the boot manager asks whether you want to boot into Acronis Recovery directly, in which case a specific recovery partition would have been created and the boot manager tweaked to ask the question. Macrium Reflect has this feature, which I've only used once as I'd prefer to boot from external media on the very rare occasions where recovery is necessary. I've not ever used Acronis.
