Kickr / Quarq Major Discrepancy

Which comparison tool is this (in printscreens)?

How about that bottom bracket? Those bearings might have way too much preload or be otherwise problematic.

You didn’t answer the chain line question. Are you cross chaining (small chain ring with small cog or large chain ring with big cog)?

Oh! Also check that your chain is properly routed through the rear derailleur cage and it’s not rubbing the front derailleur cage either. Check that the jockey pulleys spin freely by hand too.

It seems that the power loss you see between crank and wheel is real, so taking it down is worth while

Zwift power
But also happy to link to my DCR if helpful ?!

Good question re BB. Just had a brand new one installed (.during this process of troubleshooting over last month) and sadly hasn’t helped. Will check preload

Re chain line
Almost all of these are ERG mode interval workouts in big ring and center of cassette. So hopefully that’s not an issue. One thing to note is I have a wolf tooth road link (since I use a mtb cassette when not on the trainer) so that definitely has to add some drivetrain loss and chain line issue I’d imagine ?!