The Open Source Cartridge Reader is a great diy project for dumping your own roms and saves. If you order a kit with the surface mount components already installed, it’s also a great beginner soldering project.
IIRC none of the games that require the expanded RAM module (DK64, OOT, Majora) actually utilize its RAM under normal conditions. For instance, DK64 only used it as a means to stave off a memory leak.
That’s a myth, the ram was a requirement by management at the beginning of development to showcase it’s use. The ram was heavily used for the dynamic lighting. Sources: https://www.gamesradar.com/how-the-n64-confidently-signposted-our-way-into-the-3d-future/ and https://www.nintendolife.com/news/2019/11/feature_donkey_kong_64_devs_on_bugs_boxing_and_20_years_of_the_dk_rap
