For the two interviews that I had this year in EU (1 Fintech, 1 health tech, mid-level, remote, startups), I didn't prepare much other than looking what the company was doing, considering how I'd fit in there and got 2 offers.

I'd recommend to brush up the fundamentals - not in terms of knowing all the search algorithms out there, but to have a solid understanding of the bulding blocks of the web, stuff like CAP theorem etc.

Being honest about what you don't know also seems right.