Hi Kevin

my playing is still choppy and chord changes are sloppy.

This is normal and may have a lot to do with the chords you are playing. But, assuming you are on Fundamentals, they will be some of the easier chords. Slow it down using a metronome and set the tempo to whatever you need to make the transitions clean. The metronome in the tool section here will go down to 20.

I struggle to stay on task with the lessons

This is a bit more difficult. Maybe you don't actually want to learn music but want to learn to play songs. With all the resources available today you could just learn to play songs without learning the foundations of music. Example: learn the chords E major - A major and D major, you have what you need to learn many popular songs.

This has led to me feeling a bit frustrated and at times demotivating

It would be good to sort out what you want to accomplish and works towards that. This, at our age, should be for enjoyment only.

Good luck

Bill