Did Voldemort's soul only rip apart when he decided to make a Horcrux?

I don’t need to enumerate much about Voldemort’s killings. He sometimes kills randomly (for example, recall the scene from the movie where just after Harry destroys the Diadem, Voldemort gets weakened for a moment. When a random death eater merely asked if his master was okay, Voldemort replied : "Avada Kedavra!" )

We also know the fact that killing rips the soul apart:

"But how do you do it?"
"By the act of evil—the supreme act of evil. By committing murder. Killing rips the soul apart. The wizard intent upon creating a Horcrux, would use the damage to his advantage
_{^{(Horcruxes, Half-Blood Prince)}}

So we do incur damage when we murder. Slughorn also mentions that too much ripping is not too good:

"Merlin’s beard Tom!" yelped Slughorn. "Seven! Isn’t it bad enough enough to think of killing one person? And in any case…bad enough to divide the soul…but to rip it into seven pieces…"
_{^{-Horace Slughorn (Horcruxes, Half-Blood Prince)}}

We see evidence that too much ripping is too bad in book 6:

His features were not those Harry had seen emerge from the great stone cauldron almost two years ago: They were not as snakelike, the eyes were not yet scarlet, the face not yet masklike, and yet he was no longer handsome Tom Riddle. It was as though his features had been blurred; they were waxy and oddly distorted, and the whites of the eyes now had a permanently bloody look, though the pupils were not yet the slits that Harry knew they would become. He was wearing a long black cloak and his face was as pale as the snow glistening on his shoulders.
_{^{(Lord Voldemort’s request, Half-Blood Prince)}}

I find Slughorn’s point contradictory here. If Voldemort killed much more than the other wizards:

"As far as I know — as far, I am sure, as Voldemort knew — no wizard had ever done more than tear his soul in two"
^{-Albus Dumbledore(Horcruxes, Half-blood Prince)}

Why didn’t his soul divide each time he killed?
Here’s another line that tells us that only certain deaths made the cut for a Horcrux:

"He seems to have reserved the process of making Horcruxes for particularly significant deaths"
^{-Albus Dumbledore(Horcruxes, Half-blood Prince)}

Does that mean his soul only ripped when he intended to make a Horcrux?
According to this article on HP fandom, The circumstances of the murder also mattered. Snape’s soul would not be divided under the circumstances of Dumbledore’s murder, because of Dumbledore’s intention:

It should be noted however, that killing in and of itself seems not to have the same consequences to a soul as committing deliberate murder

Voldemort hardly ever killed "deliberately" (Like how Snape kills Dumbledore)
If the murders like those of James and Lily Potter are considered "delibrate", I don’t see how they wouldn’t hurt the soul. Killing here is purely of the evil intentions Voldemort has. Hence, I conclude that the soul must be damaged.

Splitting your soul would also make it highly unstable. According to HP fandom:

In fact, Voldemort’s soul was so unstable that by the time he created five Horcruxes, it split on its own when his Killing Curse rebounded the first time, which caused the fragment to be removed from him and attached to Harry.

So why isn’t his soul much more damaged than it should be?

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EDIT:
To make it clear, what I’m asking is, WHY is Voldemort strong enough even though his soul is so badly wounded? Does the soul have temporary regenerative properties to heal itself for the trivial murders Voldemort had done?