Jaime keep up with the elastics for now. Maybe prompt your ortho to do something in addition to the elastics to get the movement you need. Additional bend in the archwire, springs, whatever he needs to do to get you to your goal.
You may be on to something with your TPA limiting the closing movement; your tongue pressing the TPA and essentially keeping your molars apart. Maybe add a button above the TPA; between it and your palate to help push things down; or remove it all together. Bring it up at your next appointment; express your concerns about your timeline and how things seem to be stagnant with the gaps and a change of treatment might be in order.
I know you've been working on this for quite some time; some gains but several setbacks or minimal movement. It can be difficult to talk to a professional about your treatment; but they should listen to you and work with you to satisfy your needs! That's what I had to do a couple months ago to get more width. Guess I caught him on a good day; and he actually listened. Bringing donuts and coffee for the girls in the office can't hurt either. I've done that a couple times. You are an adult and should have some input as to how you want your teeth to look.
This quad helix expander is great!

It does work and I can actually see my #4 and 5 teeth on both sides. The tipping has stopped and it seems the teeth are starting to move out. I still have gaps between my uppers and lowers too (both sides); so I'm guessing elastics will be in my future again too. My original estimate of this December will come and go as my teeth are nowhere near as good as they can be. I want this to be the last time I have braces. I haven't kept any of the braces/ortho stuff they take off; but I think I will keep the quad helix if they let me. Just as a reminder to wear my retainers.
Round 3 (lifetime) Damon stainless applied 3/16/20 (after 4 weeks attempting invisalign) On for about 18 months
Night time elastics with invisalign retainers; still...
Double jaw surgery was 6/18/15...
Orthodontics never really ends...
I'm emphatically against extraction orthodontics!