MySQL: which default collation should I set to cover all european characters?

I noticed that my schema can't print some strings with regional characters, such as è, ù and other accents or symbols.

The manager app is a Java servlet, it has no such problems. It uses the jdbc driver. So I thought the cause could be this default collation: utf8 - utf8_general_ci.

After a research I discovered that these characters can't be saved within the utf8 bytes. Should I use utf8-mb4, utf-16, utf-32 or another? Which is the minimal best one to support all european chars (no cyrillic, arabic and asian)?

For example, this chosen answer suggest utf8mb4_unicode, but I don't see if it's really the minimal best to cover all the characters I need.

What's the difference between utf8_general_ci and utf8_unicode_ci