I checked out Baqend ("we" in the article) and the site prevents me from navigating back when I press "back" (I think by injecting itself as the previous page - I'm not really up to date on dark patterns).

This is the kind of behaviour that is an auto-no for me when buying B2B, not just by itself but because of what it signals about the company. I recommend you remove it.

On the article itself: you can do very fast pages off a relational DB. In one case, the round trip on a Postgres full text search for auto complete on millions of rows from multiple tables was so fast we had to add a 10ms delay - on a $5/month VM.