Apple - Am I able to partition my internal SSD safely without loss of data?
I am wondering if it's safely guaranteed
Nothing is "safely guaranteed." Generally speaking (as at the time of this answer your question is lacking in detail), you can (re)partition without corruption of your data. That's not to say the process is infallible. Problems happen, mistakes can be made. This is why is so important to have a backup of your data.
No - exFAT / FAT / MS-DOS are not embeddable within APFS easily out of the box. Try to not use these if you want easy. Use external disks for all these needs. If you want hard, here is an absolutely brilliant master class on how to set up a Mac for triple boot.
Yes is only if you can keep your data within APFS. You can make many volumes in the overall container and all share free space. This operation has been done hundreds of times on my test macs and I’ve never lost data or been unable to remove one volume and not get the data back or interfere with files in other volumes.
Of course, any system can crash, so keep backups but that has nothing to do with adding more volumes to the APFS container.
Just be sure you don’t partition the disk and you will be fine. Make volumes in the existing container and you are on the easy path. You would want to post details if you go off the easy path, that can cause issues like you may have experienced or heard in the past. Like the comment from David Anderson - partition has very specific meaning and you don’t want that for guaranteed and easy use of Disk Utility to make logical volumes from an APFS managed disk store.
You can resize your partitions with much more safety than just crossing your fingers and hoping there aren't any files in the section you are giving to the new partition, but you should still back up your hard drive.
Once you have made a backup and unplugged the backup, go to Disk Utility to make the changes. If you give us more details in the question we can give you a more detailed answer.