Potty Training Troubles! Help!

Hello!

I recently adopted an 8 week old Labrador Retriever and we are currently working on potty training. I've been reading ton's of articles about best practices, and I have been trying hard to stick to a rigid schedule. I've also decided to bell train her for when she needs to go out. We still have an accident or two a day right now, which is fine and somewhat expected, but the issue I'm really looking for help with is her focus when she's outside trying to do her business. From the minute we step foot outside she has her head down and her nose on and is constantly looking for something to put into her mouth. The most common ones are grass, pebbles/rocks found in the grass, leaves, or pieces of mulch. I live in an apartment building, so our options for where to go out are limited, and no matter where I take her she will find something to put into her mouth. I'd love to be able to take her out, have her do her business, and then enjoy some time outdoors, but I'm worried that her focus is a big issue when it comes to being able to potty train her (not to mention risky, as she could ingest something harmful if I'm not watching her every second). She's also very stubborn and won't listen to me when I tell her to 'drop it' or 'leave it', and I end up having to scoop it out of her mouth with my fingers, but she's learning how to clench her jaw so even that is becoming more difficult for me to do.

Any advice on how to get her to stop trying to eat everything in sight and focus on going to the bathroom? Anything would be appreciated!!

Thank you in advance!