Learn English – “I would so much like to thank you” or “I would like to thank you so much”

Are both of these sentences acceptable?

I would so much like to thank you.

I would like to thank you so much.

If both are acceptable then which one is more formal? And what part of speech is [so much]? Adverb?

Edit:
For future reference, I add some citations from Google Books and COCA as current evidences to the possibility of splitting the collocated verbs "would like" in modern English. You can do a Google search to find others but I want to quote from sources that are generally more credible.

And I can assure you, Jonathan, that as far as we are concerned, we
are going to make every effort on our part. We have done everything we
can also to create the right environment, and we do hope that the
Chinese leaders in Beijing will similarly be sincere in their effort
and we will work together to see His Holiness, the Dalai Lama, as a
solution, not a problem

MANN The people of Tibet would so much like to see him, and I know
that he would like to see them. He has been invited back to Tibet. The
governor of Tibet says that as long as he recognizes that Tibet is
part of China, he is welcome to return. Do you think he will go back?

Source: CNN Insight, 2003 via COCA

My dear Fraulein, For your dear, kind, friendly letter I would so
much like to thank you. You know, of course, what pleasure you give
by remembering me, and yet gratitude is never expressed in words …

Enchanting Jenny Lind – Page 210 – 1939

The translation is as follows : Leipzig, 2yd Dec, 1845. My dear
Fraulein, For your dear, kind, friendly, letter I would so much like
to thank you, and say how much pleasure you have given …

The life of Jenny Lind – Page 56 – 1978

In her message of thanks to the people after the April 30th
celebrations, Juliana said in a nationwide broadcast: "I would so
much like to thank you all personally, for what you have written to
me, for your gifts, and for everything which I so value …

Europe – Issue 235 – Page 244 – 1983