

They’ve been beaten on enough that industry is moving forward. The advantage of knowing and being able to prove that the algorithms are insecure would be incalcuable, so groups who want to be able to break into systems aren’t going to volunteer the information. It’s to the benefit of everyone else that the algorithms be secure. The third section of that paper I linked does a pretty good job explaining the why and why now.
tl;dr: Smart people have dug into it, and we know what we’re going to know for now.
There are four version of x86_64: v1, v2, v3, and v4.
RHEL 9 dropped support for anything prior to v3. That means RockyLinux doesn’t cover it, either. AlmaLinux has support for v2 in version 10, but there’s no way of knowing how long that will last.
Some binary packages are starting to drop support for earlier version. The latest numpy out of pip will not work on a v1 machine. You can sometimes use the system package manager’s numpy to work around it, or constrain pip to use an older numpy. I don’t know what else is lurking out there.
If you’ve got visions of taking a really old computer that you happened to max out on RAM back in the day and bringing it back to life there are surprises waiting for you.