How can I find for myself an affordable accommodation in Iceland across several websites aggregating cheap accommodation but without signing API access contract with all of them and without building a middleware to abstract them?

I don't have API for _that_.

No, it's to automate tasks that can't be done using an API, like RPA.

you're saying essentiall the same thing as the parent comment, both are true

anti-bot fingerprinting exists to prevent you from using the human-facing site like an API

...when there is an API. Often there isn't.