Potty training SOS

My 3 year old was potty trained.. then my youngest started crawling and the 3 year old started a potty regression. Now she completely just goes in her pants and thinks it’s ok. There’s my first problem.

Then my second is .. I got her to sit on the potty, she was quiet so I checked on her, she had painted my bathroom with poop. The wall, door, floor, herself. It was disgusting. I made her clean it up then left her to finish going poop. Later I went into the bathroom and notice she had peeled the paint off the wall.. is she bored while pooping or something?!

(This isn’t the first time she’s done the poop thing)

SOS any advice or success stories from similar problems ???