truck turns over but won't catch and start, how do I fix it?

What is your question?

Lights turn on. It tries to start, you hear the attempts at starting up but it just doesn't get there. There is a slight click/crunch noise almost like when someone turns the key over for to long when the rig would be fine normally. It has only done this the last few days. It would normally start up no sweat but now it won't. Also yesterday ( Aug 31st) I turned her over and it wouldn't work so I turned the key back to the off position and she pretty well started up. No burning smells, no leaks etc. I have had some Mass air flow sensor issues as well. Bank 1 and 2 are to rich. Didn't think that would cause an issue but could it be all related? The rig is used. I just bought it off a lot as is few months ago. It sat in a lot for a few months during the first shut down of covid. So I am also thinking that it could just need a new battery, plugs etc. I am hoping it won't be the fuel pump or alternator. Any suggestions on how to and what to do first?

What makes this problem better or worse?

During or after heavy rain doesn't seem to help much.

How long has your 2011 Chevrolet Silverado 1500 had this problem?

three to four days