What I think might work well for you would be some Shrimp King Snail Stixx -
https://dennerle.com/en/products/nano-aquarium/feeding-minerals-vitamins/food-dwarf-crayfish/shrimp-king-snail-stixx I get mine from
www.pro-shrimp.co.uk These are little hard sticks of approx 1.5cm long. After approx 15 mins of being in the tank, they become soft and edible. They contain carrots, kelp algae, tomatoes and spinach. Although intended for my nerite snails, my fish have taken a liking to them, even though they have shown no interest in other veggies. The way it becomes soft means that an inhabitant doesn't run off with it in the way that they would with an algae wafer - they just swoop down every now and again, take a mouthful and swim off, often creating a cloud of debris around them as they chomp on it... but which would be ideal for bottom-feeders to avail of. Sometimes I roll my eyes up at the mess the fish make with it but then know that my nerite snails will clean it up later on.
I also have a Fishmate Feeder. I haven't tried Snail Stixx in it but I reckon they might work well dispensed every few days via that method. [The reason why I no longer use my Fishmate Feeder, and therefore haven't tried it with Snail Stixx in it, is irrelevant - it is purely because my current tanklid needs to come off and the Fishmate Feeder needs to sit on a condensation tray with a hole cut in it, but at least one of my two nerites is an escape artist and could easily create a gap to escape from.]
I am more than happy to send you a few sticks to try out before buying them from elsewhere, if that would help - just PM me your address and I can pop them in the mail. If your bristlenose (and other fish) like them, then you'll probably need to test them out in the Fishmate Feeder to ensure that they remain hard in that up to a fortnight to the point of being dispensed rather than distintegrating due to humidity/condensation from the tank, and also work out how much they eat in what timeframe in order to figure out how much and how often to include this in the Fishmate Feeder.
Hope that helps.