That's not the issue: Since virtually all (x86) systems built later than 2010 are 64-bit, the expected case is 64 bit UEFI. Contemporary linux distributions don't even bat an eye at booting on a 64-bit system with 64-bit UEFI (well, there are a lot of ugly details under the surface, probably enough to keep several devs more or less permanently alcoholic; but the user doesn't need to see that).
However, there are a few edge cases that really haven't gotten enough attention and/or love to smooth them over: Apple has some older models with 32-bit EFI, and 64-bit CPUs, that are a bit weird, and there was a period where MS/Intel was using 32-bit Atom processors, with UEFI and no BIOS fallback, in order to hit aggressive price points for 'win-tablet' systems. These are a huge pain to boot to anything except the OS they were designed for; because distributions with good UEFI support almost always expect 64-bit CPUs, and 32-bit distros almost always expect BIOS booting.
There may be others; but the 'clover trail' based hardware that uses Z2760 or similar atom processors is what I'm talking about.