What is the best easy-to-read free font to read?

Question

Design

I want everything in it to be - in moderation!
Design. not too intricate - (with squiggles, serifs) but not soulless either. The letters are not angular but slightly streamlined. Not too elegant but not clumsy.
Easy-to-read letters that cannot be confused
Proportionality of letters . Density. So that the font is dense (compact, condensed) but not mushy to the point of ripples in the eyes
Lines of letters so that they are not very different but not the same thickness
Capital and lower case letters in size so that they have a harmonious difference. And not uppercase - huge, but lowercase - barely visible
Punctuation marks so that they are clearly visible, without modesty
And so that the letters "d" and "l" look like this (marked in blue)

Answer 1

Calibri?

Answer 2

I'm addicted to Echo 2.

Answer 3

The font must be chosen based on the function that it should perform. If you plan to place it in print media where there is a lot of literary text to read, then you need to take a serif font. The brain, due to serifs, perceives the line even before you read it. If you need a font for web interfaces and large text arrays, then my favorites are Lato, Open Sans. The most readable and pleasing in any size. For headlines, I love Montserrat, a stylish yet simple typeface.