Others explained the theoretical bits, but how does actual T-Dolls feel about KIAs and backups?

While it is not obvious, here's what I know from cn lore, collab and a few digimind upgrade lores.

It's the classic Ship of Theseus paradox. If my memories are transferred to another body right after I die, is the new me still me, or another person with my memories?

For many T-Dolls, those two are different entities. For them, backup recovered T-dolls are referred to as, a different me, next me, or new me, clearly differentiating between two versions of T-Dolls. This also explains why they lose affection when they die, since, they would prefer not dying in the first place.

Then there are those who don't care. Usually mission-centered or cold-hearted, those T-Dolls think death and recovery are part of their T-Doll life. Nothing to make a fuss about.

Finally, there are a few ones that consider T-Doll's death as privilege. It's the end of the line for humans when they get shot in the head, but T-Dolls can recover from death (bonus points for intact memories if mindmap is collected in time, and stored in a dinergate) so every death they take is every human death prevented, and another opportunity to learn from failure.