Mom's in an independent living apartment for 5 weeks but I dread going there and I feel so guilty.

This is not something you can reason with. Part of dementia is losing your ability to smell bad odors, like urine/feces/rot/smoke/fire/etc. That part of the brain stops working, and it causes a real safety hazard.

Personal hygiene becomes a problem because the person fears falling, being cold, the noise of a bathroom is disorienting, and the general difficulty with processes and change as well. Bathing yourself is a process, and if your brain can't do sequential steps anymore, it's not going to happen. If you can't smell yourself and clothes anymore, it's not going to happen.

It's time to bring in more help for mom.
Sometimes the adult child can't own any more burden. I'm one of them. Nobody took over my house payment and bills when mom went into the care facility. I physically can't help her transfer, change, or stand up. And being permanently 5 years old to her, I am the last person she will allow to do things for her.

At my mom's IL place, you can add on housekeeping, laundry, and help with the ADLs (Activities of Daily Living), and meds. At some point though, mom's decline will increase and she will need more than you can get in IL because she won't be independent anymore.

We had my mom on the waiting list to move into the Assisted Living unit on the same campus, but she took her diabetes pill, forgot to eat, and passed out in the bathroom. When she came back from the hospital, she actually skipped over AL and went in to the skilled nursing care unit instead. These were not decisions she could refuse or control, and it was all in her best interest. She is now in secure memory care, but starting in the skilled nursing unit, they bathed her, changed her, and got her food to her, meds, etc.

Talk to the social worker or head nurse at your mom's IL to get more supporting services added on. They can usually put a package deal together for you.

Refusing to bathe seems to be a common problem in early cognitive decline. I can understand you felt it better to care for your mom at arms length rather than have her in your own home, but the difficulty with that is she is not functioning very well independently. It could be she is afraid of falling when she is alone, it could be she is just resistant and a prod from a neutral party will get her moving in the right direction. Perhaps once a week an aid could come in, do some light cleaning and at least help her start her shower. Of course she will probably say no to that, but if you are firm she will hopefully accept the help.