So today I put my sim in my Pixel 4 and gave it a thorough test.
I was off work today, so have used it as normal throughout the day, taking photos, uploading stories to Instagram, listening to music, checking emails and web surfing.
Nothing heavy at all. No games, no YouTube vid watching, no streaming content (music aside) and these are the results.
So it got me through the day (I'm in bed now) with the battery on 14%, but by and large this is quite low usage compared to a weekend day where I wouldn't be going to bed for at least another hour and would likely have been up earlier. I also didn't do any YT browsing today which is something of a norm for me most days.
All in all, quite disappointing.