I have had very good feeding from Glassgarten I use Shrimp Baby and Shrimp Fit +, but I went to look at it on their website and it is now missing.
They have the Betaglucan +Immunoglobin (I haven't ever used this one by that name) maybe that replaced Shrimp Fit. The shrimp go straight for/ immediately to these foods. Especially all even adults to the Shrimp Baby which are small granules, and oddly, the ShrimpFit is more like a powder. And every week or 2 will add the Mineral Junkie Pearls. I started out using their BacterAE, which if you ever decide to try it, I would recommend just the very tinyist amount and only 1 time every week, maybe 5 days. I would frequently see a dead shrimp after adding like they suggest in the directions. But no issues using just a tiny amount. My tanks for shrimp are usually 5G, 6.6G or 12G sizes.
Another option if it is available to you and I use lots of foods for the shrimp, but mostly lately the above and Shrimp King 5 in 1 Sample pack. They all like these foods as well and will go straight to them. I rotate a little bit of the extras with a small amount of the complete. Feed it every other day, and they come in an extruded pellet form and you can just break off a little piece whatever size you need for them.
There isn't a huge amount of food but for a small colony may last 6 -8 months.
You really don't need to buy a large quantity either because unless you have hundreds of shrimp I have foods which have lasted years now. Just keep their lids on tight and in the more dry area out of sunlight.
You might also find someone on Amazon offering a food sample pack where they repackage the foods in little bags and JungleFowl member here has a business and offers some packs https://www.jungleaquashrimp.com/
may also have something on Amazon, Oh, Benbachi foods, he has a sample pack for I used those prior to these, and really liked them as well. Bought many times from him over the years sample packs and dried leaves, highly recommend his products.
But also mention over feeding. The shrimp have a tiny stomach but graze all day long, so feeding a tiny amount for them is fine. I often have micro fish with my shrimp (only a couple kinds due to predation) and they get fed 5 or 6 days out of 7. So shrimp get plenty of food all the time. Plus established tanks biofilm and Aufwuchs.
Any how, I would also recommend feeding much less amounts of food but a little more often for the ADF
benefit. Because of the BB.
and as for the shrimp finding the glass dishes... Fast the tank for a day or more and then add the glass holder in an area you usually see the shrimp eating in and they will likely find it since they are more hungry.
But maybe consider letting the ADF
have their own tank with a few fish. That way they get more possible chances of food. They usually have trouble finding their food!