First, only 8 applications! That’s fantastic - I likewise am starting a senior software eng role… but after 6 months of unemployed full time interviewing, and around 80 applications. FE, not BE, though.
In terms of content, I think every coding round required time/space complexity analysis, and (as an FE!) most had me doing things like building recursive binary tree checkers, solving medium Leetcode problems, etc.
> I made a point of challenging it and asking whether it was representative of the role
Yes! Love this. I had a systems design round, which are usually my time to shine, that focused exclusively on designing an app’s database. A DBA I am not, and I essentially flunked. I brought it up to their CTO on a later call, as I really didn’t think that was a fair assessment of me.
That wound up being the place that hired me :)