Is The Silmarillion a "downer"

[Tuor of Gondolin]

A view of The Silmarillion, and, it seems, one shared by JRRT, is that it is a generally depressing work. For example, in "Letters" #247 he says:

...many of the older legends are purely 'mythological', and nearly all are grim and tragic: a long account of the disasters that destroyed the beauty of the Ancient World, from the darkening of Valinor to the downfall of Numenor and the flight of Elendil.

Yet I think a case can be made for The Silmarillion being generally positive in many of its stories and philosophical underpinings.
For some: The Tale of Beren and Luthien, Tuor (with amplification in UT),
the influence of the elves in turning back Morgoth from a quick domination (except for Doriath) of Beleriand, the necessary time gained by the exiles
presence for Men and Elves to interact culturally and politically, the half-elven, etc.

While The Silmarillion has elements of Greek tragedy, there is also always
present the striving and hoping , by many elves and men, for a
"redemption" of their increasingly hazardous situation, and one that is
eventually realized.

So, how do you view The Silmarillion, as a depressing work, an essentially hopeful
tale, or in some other way? With the exception of Hurin and his family, are the tales all that depressing? They seem to me to be a mix, especially with the tragic, ambivalent figure of Maedhros.