If you lift like this for a long period of time then you will get stale-as your bench has. Don’t train to failure. If you elect to do so only do it once every 3-4 weeks. While it may have worked with your squat, it clearly is not since you state you have leveled off for months now. There is really no need to go to failure but if you do so, do it infrequently.
Sometimes you get stronger by going lighter. Especially as a true unload week. You have to trust that backing off or not blowing it out every week is not necessary.