Any suggestions for best non-slip tub mats and are suction grab bars safe?

Wow I never thought my question would prompt such a great discussion. So I’ll definitely not use those suction grab bars. I will probably have to get something professionally installed. I installed all of the other grab bars in the house, but they were easy to do because they were on door frames (old house, 3 inch thick solid wood on both sides). Actually, I do have sliding glass doors, but the good news is that if I remove those, I can place at least one bar where the vertical track is installed.
It’s true about the danger of towel racks. When I installed the toilet riser with hand rails for my dad prior to his coming home from rehab, my mom (who was in pretty good shape back then) said she really appreciated that because she’d been using the towel rack to pull herself up!