Depends on the age and spec of the 64 bit PC.
If you're talking about a 10+ year old, 64 bit i3, with 4-8Gb RAM - that will happily run any modern distro. I know that for a fact because my current laptop IS an early, first gen i3 and that will still happily run any 64 bit Linux distro.
But if you're talking about a 15-20 year old 64-bit Celeron with 1Gb RAM - you're probably going to want to run a 32 bit Linux on it.
Some of the early 64 bit PC's - especially lower-spec ones, don't perform well with 64 bit operating systems and perform better with 32 bit OSes - especially those with 2Gb or less of RAM.
64-bit programs require more memory to run than their 32-bit versions. So on older 64 bit machines, with less RAM onboard - it makes more sense to run a 32 bit OS.
That situation can easily be mitigated by installing more RAM. But if you don't have that luxury - then sticking with a 32 bit OS is your best recourse.
It's worth bearing in mind that a lot of low end PC's are built with a minimal spec that will just barely run whatever version of Windows was available at the time it was made. Many OEM's shipped some of the early, low-spec 64-bit PC's with 32-bit Windows installs because their spec was too low to smoothly run the corresponding 64-bit version. And 64-bit Linux doesn't perform much better on these older machines either.
That is exactly my own experience with 32 vs 64 it OS on low spec devices.
I tired to salvage an old dell with as far as I remember a 2g plus celereon,
that was a painful experience, the ram was only 1GB, that ps had no intel IME,
which was why I wanted it, I hate spys, that lead me to Raspberry Pi 48GB models,i
which I find very usable with a 24 inch monitor, but they were not so portale in that
a monitor for one is costly, as is a power pack to drive the Pi, so I bought a much
cheaper low end laptop, that am very surprised works, even with a 64 bit OS,
If and when this / MX Linux lets me down, I will give 32 bit a run, until them am happy
with this inexpensive travel companion / emergency device.