reliable soil sensors

Sorry, but something like that doesn't exist for soil, it's physically impossible to get reliable values on pH and EC, and not really data you can use when growing in soil. The moisture (and auto watering) part can be done with Bluemat plugs, and the rest can be automated if you use a resevoir, or calculated if you have data from previous grows. FYI automated grows often end up requiring much more daily work than simple hand watering, so do it for the fun of it and not for the results :)

The moisture ones will work in a precise manner, but there are inherent issues that reduce precision of reading soil pH. They are accurate devices, but the context is what causes the volatility in measurements. e.g. The moisture content will potentially impact the pH reading. As volume of water reduces and solutes get more concentrated, you get a change in pH and EC. i'm sure it can be useful information to track, but i wouldn't assume things based on what it tells you the first time you use it... what you see is likely what was happening all along before you bothered to look and may not be a bad thing... (assumes healthy, fast-growing plants being your norm). It'll probably take expereince to delineate between what the plant is causing on its own vs impact of evaporation. What to react to and what is normal ebb and flow or false positives. So, when you do set it up, maybe get a few cycles of data before using it to support any significant reactions. then, can try a little trial and error to refine things using the data.

Care products are expensive, but if you'll watch after it, will last very long. https://bluelab.com/products/bluelab-soil-ph-pen?srsltid=AfmBOooZYQ8nEVeaHFv2TiNQ4kOKRGo2neckF8XaW7NMtY30u_pFsFp8 Any meters for 10-20$ on amazon is scam.