This is true, so as DM you will hand wave these rules then? Just curious how you will tackle when the Monster at high level targets the PC with the low stat. Or the PC targets the BBEG with the low stat with a save or suck round 1.
I sort of answered with my reply above. In the case of monsters, again, I am the DM. If I want the BBEG to have a low stat and thereby a low save, then I guess I am ok with PC getting off a SoS round 1, right? If not, then as DM I have to build the BBEG appropriately.
(no longer speaking directly at you, now just ranting a bit

All these "this or that" is broken when its PCs vs DM is silly and largely pointless. In a PC vs PC game, I can see that, but that is not what D&D is. And while, yes, DMs build NPCs like a PC, its an investment of an evening, not many multiple hours of gaming sessions. If NPC(monsters) are road bumps to the BBEG, I build them to DIE. If they are the BBEG, I build them to be a tough challenge. If they are "not to be trifled with" I build them to not be trifled with (i.e. they dish out SoS and are largely immune to SoS e.g).
As DMs, we adjust encounters to the PCs at
our table. I build different for 12 year old noobs than I do for my 40+ grognards. Every DM, at every table, has to adjust. If they don't, that is when things "break". The game will totally work if people you use RAW saves but adjust NPCs/Monsters to suit the encounter accordingly . It will also work if RAW rubs you the wrong way and you make an adjustment to saves as suggested by others up thread. No matter what you do or don't do re:RAW, you'll be adjusting NPCs/Monsters to suit the encounter. IMHO, I think its easier to just adjust NPCs/Monsters to suit the encounter period, instead of adjusting both saves
and NPCs/Monsters.
It's only broken if you let it break.