You didn't mention tren and that's a big one that you should not have overlooked.
You don't mention training either. How do you train to keep strong if you have been stuck at same bp of 405? Do you over train? Too long, two-three days on then one off. Hows your sleep and diet?
Do you diversify your workouts every two to three weeks so your body doesn't adapt and stagnate?
I would drastically switch out weights and add more reps and more volume then go back to lifting heavier in two weeks. Then rinse and repeat.
Give your androgen receptors a frickin break. Your body in a continual pursuit to balance itself. Gains seem to slow down after a few cycles, and the need to keep upping the dose has more to do with the body attempting to return to homeostasis.
When you drink a cup of coffee every day, then find you need to keep increasing the size to get the same caffeine punch doesn't it make sense to reboot?
You should cruise at a much lower testosterone dose.
Can I recommend 150mg-200mg/week for two months. You will keep most of your gains, it's just harder. Some of it psychological. Blast then cruise at TRT levels.
One gram of testosterone/week for cruising is just way over the top.