Re: Official PDFs from Nintendo's websites.

https://www.nintendo.pt/Assistencia/Nintendo-64/Manual-da-Nintendo-64-e-documentacao-adicional/Manuais-de-jogos-para-a-Nintendo-64/Manuais-de-jogos-para-a-Nintendo-64-990819.html

This page, from the portuguese Nintendo website, has 19 Nintendo 64 game manuals.

Searching for 'website:nintendo-europe.com filetype:pdf' yelds a lot of results.

While it may not seem like it, nintendo-europe.com is an official Nintendo website. In fact, https://www.nintendo.com/regionselector/ has a list of official regional websites. The polish one is in the domain nintendo-europe.com.

Some examples:

Dokey Kong 64 (source pdf, not a scan)
https://fs-prod-cdn.nintendo-europe.com/media/downloads/games_8/emanuals/nintendo_8/Manual_Nintendo64_DonkeyKong64_EN.pdf

The Legend of Zelda: Ocarina of Time (hi-res scan)
https://fs-prod-cdn.nintendo-europe.com/media/downloads/games_8/emanuals/nintendo_8/Manual_Nintendo64_TheLegendOfZeldaOcarinaOfTime_EN.pdf

Forgot to mention: since there are official nintendo websites hosted at different domains, for a thorough search, one would have to also try all of them, such as nintendo.co.jp, nintendo.de, nintendo.ca etc.

This website has a list of official nintendo websites, but I'm not sure if it has all of them: https://nintendo.fandom.com/wiki/List_of_Nintendo_websites