I was thinking about a simple method for brewers who use the stovetop and biab/pot for small batches.
For the mash, why not buy an affordable inkbird fridge controller and plug the heating element into the controller. Then set it at 152F or whatever temp you want and it will automatically cycle on and off as needed during the mash.
Another option is a sous vide stick set to temp, it will heat the wort as needed to maintain temps automatically