Alhamdulillah, I am financially well-off.

Answer

While it is permissible to open more shops, it will only add to your problems, occupy more time, decrease your free time, bring more worries, weaken your bond with the Deen, etc. In short, it is not advisable. Rizq is predetermined and fixed. Rasulullah (sallallahu alayhi wasallam) said: "Restrict your search (for Rizq). Rizq is sealed and the greedy one is deprived."

Free time is a wonderful ni'mat. When you are earning comfortably and when there is no shortage, then it is not advisable to expand into the dunya. Maut is always stalking us. We have to make preparations for the stay in Barzakh. Rasulullah (sallallahu alayhi wasallam) said that the most intelligent person is he who makes preparations for the sojourn in Barzakh and the Aakhirat. The Qur'aan Majeed says:

"The life of this world is but play and amusement while the abode of the Aakhirat is best for those who adopt Taqwa. What, do you not understand?"