Remember to turn off breaker to the oven before starting any work.
I did a quick internet search for the slow heating problem and immediately found the likely cause was the lower bake heat element. I confirmed that the element was not heating well and went to Appliance Parts Pros web site to find the part. With my oven model no. it was easy to find, as usual. There was even a video, which I was hoping for. Ordered the part from them and it was here in a few days. Never a problem with APP!
The repair looked very easy, and it was. The hardest part was loosening the screws, but with a little force they came right out. I did find one tip from somewhere else that suggested I be careful and not let the wires to the heating element slip behind the oven wall once they were detached. To prevent that I clamped some small clamps (I used hemostats) to each wire before detaching. I also had to use some needle nose pliers to remove the wires as they didn't want to just slip off and I didn't want to pull too hard. Came right off with the pliers.
Attached new element and replaced screws and that was it. Quite easy!