In this case, a 64-bit little-endian unsigned integer Ought to be enough for anyone. [1]
Using variable-length "micro-compression" schemes like these merges concerns [2], add processing overhead, and lose out on the simplicity and efficiency of working on the data directly in memory, maybe even reusing the same memory/cache line after checking identifiers, etc.
The 7-bit VLQ scheme [3] makes sense for MIDI sequences (1980s), as they were stored on MIDI hardware with limited memory, and had basic processing needs.
[1] https://quoteinvestigator.com/2011/09/08/640k-enough/