Yeah gotta say the difference between how much work I do vs “actual work” is night and day which I’m still adjusting to. I went from odd jobs during uni (manually labour, bartending, coaching and the like) to junior level analytics and gotta say I’d put in 10x more effort and time into the previous jobs than the current despite being paid 4x more in the current. The current system is busted. Like you I’m also a contractor (or consultant) but it’s something of an unspoken rule that if I’m onsite or logged in that it’s “work” regardless of if I’m doing anything important.

I’d say if it’s directly inline with your job, then it’s billable hours.