Recovered MacBookAir and the availability of Pages/Word and Numbers/Excel

I recently recovered a MacBook Air (new Wifi card, new battery). It's woking perfect under Big Sur (newer versions are not an option).

Unfortunately, using Word and Excel, as well as Pages and Numbers seem to be impossible. Using the latter seem to be possible only if you downloaded them previously from Apple Store. And since this is my first, this is perhaps not an option.

Question to the audience, can I stop searching for what appears to be impossible, or does someone knows a possible solution???