I haven't used it before but Firebase/Supabase is probably the way to go if you just need to save and load data from the frontend. Fireship is an entertaining and instructive channel with some videos on it:
edit: to clarify, you don't need a server at all for what you're doing, just a database with an API, which (as I understand it) is what Firebase and Supabase offer. Firebase in 100 seconds by the Fireship channel: https://www.youtube.com/watch?v=vAoB4VbhRzM
https://youtu.be/9kRgVxULbag
edit: to clarify, you don't need a server at all for what you're doing, just a database with an API, which (as I understand it) is what Firebase and Supabase offer. Firebase in 100 seconds by the Fireship channel: https://www.youtube.com/watch?v=vAoB4VbhRzM