There are two limits...
#1 No camera can record a single clip of video which is longer than 30 minutes (they cut off at 29 minutes 59 seconds). This has to do with a tariff imposed by some countries (it does not apply to the US). There's a different import tariff for "video" cameras than there is for "still" cameras. But in the age of digital, every camera can record video. So the treaty is that the camera wont be treated as a "video" camera unless it is capable of recording 30 or more minutes of video (continuously).
To avoid the tariff, DSLRs cut off recording at 29 mins, 59 secs.
Not every country imposes this tariff (the US does not), but since the camera is designed for global distribution, it effects every camera regardless of which country you live in.
The second limit is a bit different. The FAT32 filesystem has limits in which no single file can be larger than 4GB. Older cameras would stop recording. Newer cameras continue to record -- but they create a new file. E.g. if a single clip would have been 5GB, then you'll get a 4GB file at which point the camera will close that file and start a new file which contain the next 1GB of video. This is a limit of the FAT32 filesystem. A 64GB card uses the exFAT filesystem (instead of the FAT32 filesystem) which does not have this 4GB limit.
The total amount of recording time will depend on the resolution and framerate.
See page 334 and 335 of your 7D II instruction manual (the full version of the manual, not the "Basic Instruction Manual" which is an abbreviated version.
Note that the times listed on those tables are estimates because the video formats compress the video. The actual recording time will depend on how much your subject matter can be compressed.
12/05/2023: New firmware updates are available.
09/26/2023: New firmware updates are available.
08/18/2023: Canon EOS R5 C training series is released.
07/31/2023: New firmware updates are available.
05/18/2023: New firmware updates are available.
03/30/2023: New firmware updates are available.