As an assistive technology and ergonomics specialist, I have worked with a number of people in your situation. As you indicated, even when using VC with Dragon, there are times when it is more efficient to be able to use a physical mouse. One frequent solution I recommend is to “separate the mouse from the click.” If you have a mouse device that you feel comfortable using to move the cursor (trackpad, trackball, vertical or standard mouse, etc.), you can use a separate switch–typically with your non-dominant hand–to generate a mouse click. (Or hold it down for dragging actions.)
Most often, I recommend the AbleNet Micro Light switch as it only requires very little effort to depress and can easily be positioned as desired—I sometimes Velcro it to the side of the keyboard or stick it onto an old CD disc and use the weight of the keyboard to hold it in place in the desired location. I have also set people up with a larger switch mounted next to their knee. Some folks have done well enough placing a second mouse under their non-mousing hand and just using that for the mouse click. Whatever works for the individual.
For connecting the switch to the computer, there is the Swifty USB switch interface made by Origin Instruments. (With a 1/8” stereo to mono splitter, you can connect two switches for left and right actions.) If you or a friend are handy, you can crack open an old mouse and solder a 1/8” mono jack across the internal mouse button switch to accept the external one.
This can be a lot less taxing than saying “Left or Mouse Click” constantly and dragging to select text can be a challenge—unless one uses the click (at the start of the text block) + shift-click (at the end of the block) strategy. [by voice, you’d say “press shift left click”]
Here are a couple links:
Micro Light switch: Amazon.com: AbleNet Micro Light Switch : Tools & Home Improvement
Origin Swifty USB switch interface: https://www.schoolhealth.com/swifty-usb-switch-interface-beam-wireless-transmitter?scid=scbplp87161FL&sc_intid=87161FL&msclkid=88055ce8137b1c28245f3dfcb4c87cf0&utm_source=bing&utm_medium=cpc&utm_campaign=SC%20Shopping%20-%20Branded&utm_term=4577610505385347&utm_content=SC%20-%20Branded