Hi Op
Meet billypup, exactly the same breed mix, but 1 year older. If you check back on my username for about a year ago, I had 3 recall threads in quite quick succession.
One day I was in a field, doing basic training with her on longline and a lady was there doing gun dog training, her dogs were incredible definitely something to aspire to. She said that one of them were on they transfer list at that age, she also said retrievers don’t mature until around 4.
We still have similar issues, she now only goes off lead in a secure field, attached to a longline. Recently she’s been amazing, until yesterday when she was awful pulling dreadfully on the lead.
My advice would be to stop walking her and start playing with her in different locations. Play focus games, we’ve been doing gun dog training, which is so much better than obedience for her as it works with keeping her focus in the environment that she’s in, dog classes were a waste of time for us, , the environment clinical and the same each week, she was bored, but happy to get training treats.
Also unless it’s secure keep her on a longline, it’s much less stressful.
Try agility as well, both are intelligent breeds and getting her to use her brain will tire her out and really help calm her down.
I also think from what you’ve said you are a little overwhelmed, maybe pick one behaviour to start with and focus on that
You’ve got this she will calm down.
And 💐 for you wishing you all the best for your diagnosis