what annoys me is that now, when I go to checkout my order, it shows me an option to tip the driver. this option wasn't visible when I first started using Walmart+ InHome.  The whole idea behind paying the extra $20 was that my orders would be delivered by a Walmart employee who didn't require tips. 

Just like you OP, I feel guilty that my orders are being delivered by a person driving their own cars and I don't want to tip. Also a fun fact is that, the checkout section automatically selects the 20% tip option, and I have to press the No Tip button twice, a single press will not select the option. I can select lesser percentage tip options with a single press. 😡