One Idea i had was to create a Collection of RenderTargets that contains prerendered chunks of Ground Textures, and only draw those affected by the View Matrix. But i dont know if this will impact memory usage negatively.
For a static map i think render targets would work well either way zoomed in zoomed out.
However mip maps are typically used for zooming out to avoid down sampling (minification). When tiles must be dynamic you can cheat by just using the default point clamp filter or point in a shader for the minification filter.
I actually made a rough basic example for dynamic tile mapping recently below, this however has nothing to do with a render target solution which for a static map is probably the better choice.
draw-2d-grid
There are other solutions on that post as well some more relatable to what you are doing.