Hi
@Vanadia and welcome to the forum.
I have a couple of bristlenose plecs in different tanks, with various tetras and corydoras. All of my tetras will eat algae wafers, but I've not had any problems with fin-nipping.
I'm not sure if a plec can survive on veggies & driftwood in a tank, though I guess they don't get any wafers in the wild.
There are a few things that you could try.
I have grown algae just by putting the rocks in some old tank water in a container on a sunny windowsill. A small pinch of fish food will provide nutrients. It takes a while to get a good growth, but my BN's love them.
You could also try leaving the tank lights on for longer, to encourage algae in your tank, but that can be quite a controversial approach, depending on how pristine you like the tank to look.
I'd also think that a variety of vegetables would provide a broader range of nutrients. My BN's and other algae eaters have eaten courgette, cucumber, carrot, and baby sweetcorn. There is a huge list of things these fish will eat, though some might be a bit trial and error to find things that they like. Others on this forum have used sweet potato, sweet peppers, and apple. If you have a search on the internet you'll find lots of different things that are considered suitable.
The other thing that I do is push algae wafers into softer veggies like cucumber and courgette. My tetras will nibble on these, but it keeps enough of the wafer "hidden" so it might provide your plec with more of a chance to get some.
Does your BN have a favourite cave of hiding place? My Bertie does, and I tend to put some cucumber with wafers in right in front of that. If you can do something similar it might reduce the access for the tetras, and again give your BN chance to eat undisturbed.
I hope that this gives you some ideas.