Proton Decay - What Happens? Is there a boundary? What's the future? Questions

Hey there,

I want to give a forewarning I'm only a space enthusiast, so I do not have the knowledge some of these wonderful folks here will have. With that being said, please go easy on any mistakes I make. I wondered what exactly is the future of Proton Decay? So the theory goes that Protons decay over an extremely large and incomprehensible amount of time. This being said, there are some questions I have that come with this.

First of all, if protons are actively decaying, I can't imagine that nothing would change between now and the end of Protons existing. I see the possibility that, as the proton decays, so does the way of life and mechanics of how protons/atoms work. In my mind, if you offset such a thing enough, eventually, you're going to start seeing differences from how it was before. So, in our era today, protons might behave a certain way now due to the stage they're at in decay. However, is it possible that, with enough decay and time, say well over half the proton has since decayed, that seems like enough to alter some fundamental understandings of things. If I'm incorrect, we have the mass of a proton currently. However, in enough time, that mass will change very noticeably. I can't imagine this having no effect whatsoever on our universe. But as I'm not learned in this subject, But I would be curious, if it is the case that this causes significant changes with enough decay to protons, then I wonder if there is a "point of no return" where Proton decay has decayed so significantly, that perhaps life is no longer possible, or perhaps the way things operate no longer operate the way we know them to. Rather than this moment of waiting for when the proton fully decays and then it all happens, it could be that it's continuously happening and changing.

I also wonder how it would be like for a life form / organism to experience proton decay in real time. If you were an outside observer, what would it look like if you happened to time it exactly where, let's say 20-99% of the protons in this organisms body had either fully decayed, or decayed enough that it causes some reaction. What exactly would it look like from an outside perspective? Would you simply see matter "vanishing" before your eyes, or is it something more complex?

I realize some of this may need to dip into fantasy land, but I hope you'll humor me and "play along" with some of these questions.