Just when you thought you've seen it all during a round of golf ...

What has gone downhill? Have you been practicing properly, filming your swing, working on exactly what he suggested without straying? My thoughts are that your results/outcomes from a lesson a year ago probably aren't all that relevant anymore.  And carry distance is far more important than total distance. Total distance is going to vary significantly based on course conditions.

One thing that has helped me tremendously is to spray the club face with foot powder when I am on the range. Seeing ball impact can be quite helpful if you are hitting shots all over the place. It's not the cure all, but a good little thing to do on the range. The other thing, and I will forget to do it, is the pre-shot routine. Find me a spot a foot or so from the ball in-line with my target, take my stance, take the swing.  Sometimes you take a BS practice swing with no thought. Make it deliberate.  As far as swing thoughts. I have 3 check-points. First is set-up, Second is my take away, Third is my downswing. I cant explain what I think I just know in my mind. Its a feeling that I have that feels right and experience has shown that if I follow those 3 thoughts more than likely the outcome will be what I was looking for. Now, thinking about the feeling and executing it properly is a whole different thing, that;s why I practice, I used to be over a 20 handicap, I am down to a 15.1 in about a year.  I feel like its good progress. the goal is a 10 by the end of the year. If I make it great, if not, hey at least Im not in Gaza. LOL

I usually shy away from giving advice on a golf swing since so many here are more qualified than I am.  You might try the following:  Create a "MySwing" page on this  site and you will get a lot of good advice Filter all of the advice and try to only focus on one or two things at a time.  Unfortunately it is very hard, if not impossible, to constantly change different things at the same time.  Figure out what is the most important thing to work on at this moment in your golf swing and focus on that until you have it engrained, then move on the the next change. Remember, we all have both good & bad shots.  The difference between the pros and us hackers is the ratio of good to bad shots. Understand that a bad swing can occasionally look like a great result and a good swing can occasionally have a bad result.  The key is to focus on one thing and work to get that as consistent as possible.  Ideally that will gradually increase the number of good shots vs bad shots.    Do not forget to have fun.

So close, that is frustrating.

You need to stick with one instructor as long as they’re not terrible. There’s no blueprint to improving a golf swing and different instructors may see different things as being more important and try to fix them. The end result is you get a hodge podge of things to work in that may not be cohesive or necessarily help you. If you stick to one instructor and communicate to them as such, they’ll also be able to work out a roadmap to your improvement which is more beneficial in the long run. If a guy assumes you’re just coming in for one lesson you might end up with a band aid.