Tips for caregiver burnout leading to loathing and resentment?

Since May 2020, mid pandemic, I've been taking care of my mid-stage dementia ~75yo grandmother. I've been experiencing burnout on and off, and only have taken 'time off' during surgery recoveries. I'm fortunate that I only care for her during weekdays, and for only eight hours, but the weekends don't feel like respite anymore. I've found myself loathing her and her quirks.
She was always the 'fun' grandmother who burned bridges due to her immaturity. When her second husband passed, she had managed to burn the bridge with her youngest son (my father) when she wouldn't stop demanding pity and not allowing others to grieve, as 'she was the one worst affected.'
In her dementia, this attitude has bled through with attention seeking and dramatic behavior. She becomes extremely jealous of my 4 year old niece, and will go into meltdowns about being 'left out' despite actively participating in the activity.
Being autistic and traumatized, I've always struggled with maintaining 'idle' chatter, and typically only spoke when spoken to. I've gotten better at it as I've cared for her, but some days, if I'm not speaking to her constantly for 4+ hours, she will go into a meltdown over being 'ignored.' She has no interest in folding clothes, reading, chorework, and turns commercial breaks into chatter/wander time.
As of right now, I am exhausted. I sneak away from her to the kitchen just for a few seconds to breathe and try to calm down. My parents 'aren't ready' to place her in a facility, and they're avoiding hiring a day nurse or assistant.

I'd appreciate tips on ways to destress from the daily sensory overload, as well as tips on distracting her so I can breathe for a while.

I apologize for the mild rant in backstory.