After years of mucking about with “chocolate block” connectors, I have now learned how to get the correct connectors for the boiler element terminals. The connector part number is 160783-6 or 160783-7 (or any digit after the dash from what I understand).

And for the plastic cover, there is now a 3D printable solution designed in collaboration between me and Loogle from the Gaggiuino discord server.

Here’s my YouTube video about installing the connectors and printing and installing the plastic covers: