ukph1840 and zuluwar24 are sellers on eBay
who live in St. Louis. You could message them.
There is a stamp club down the road in Columbia.
The St. Louis Bears can be found here: http://www.stlouisbears.org/
Besides David Straight and Dr. Nettles who were founders, there are others of known names who have been or are members. For example, G. Scott Ward, who passed in 2019. was the person described as, "A member in 2009, who had never exhibited before, received a Gold the first time out." Scott went on the win many gold awards and large gold awards when Large/Small Golds was introduced for later iterations of his Usages of US Parcel Post Stamps 1913-1926. With the 2019 Great American Stamp Show providing his last gold, a Large Gold Award a few days after his early and untimely death.
They, the St. Louis Bears, can point you in other directions as well.