It depends on how much you want to spend. There is a company that makes custom and large breed coats (I believe out of Australia but ships worldwide). I have not ordered from them yet but a couple of Danes I follow on Instagram do and their coats are really nice. Here is the link: https://www.mila-me.com/.

I had this coat for last year that fit our Dane but she is petite with a deep chest (110 lbs and 38 inches around the chest). It actually fits well and is fleeced lined. The measurements on the description are relatively true to size: Didog Reflective Dog Winter Coat Sport Vest Jackets Snowsuit Apparel - 8 for Small Medium Large Dogs https://www.amazon.com/dp/B07YB2CGT8/ref=cm_sw_r_cp_api_glt_fabc_3TTRTJJMZMDEB71GTC85?_encoding=UTF8&psc=1

Good luck!