I'd suggest speed modules in the wells, and speed beacons surrounding the wells. They're infinite like vanilla oil. They're somewhat depleted, but only down to a minimum of 25% of their original value. So speed lets you get more, indefinitely. And productivity is watered down for mining since it's added to the passive mining productivity bonus from tech.
Use exploration drones to reveal more of the map and find more volcanic deposits. They get bigger the further from the origin point you go.
Where is most of your sulfur going? You usually don't need vast quantities. If you have sulfur shortages, you should stick with the hydrochloric dust dissolution recipe rather than the sulfuric one. If you're getting all your rutile with sulfuric acid, consider making more use of the silica byproduct recipe. You should be able to get most of your rutile that way and only use the sulfuric recipe occasionally.
Many of the core uses of sulfuric acid return some sulfur dioxide byproduct, so make sure to capture and reuse it when possible.