I recently bought this feeder for my 20 gallon tanks in preparation for an upcoming 2 week vacation. I tested them yesterday and they work great. They do have a clamp that you can use if your tank has no lid. One of my tanks has a lid so I just set the feeder on top of it with the feeder opening above one of the cut-out areas of the lid. You select the size opening on the feeder so that it doesn't dump too much food out.
Your particular tank and lid look a little tricky as it appears to have some curve to the lid. I can't tell from the photo if this feeder would work given that slope but it might.
Otherwise there are some vacation feeder blocks that you can put in the tank that dissolve slowly and the fish can eat at them over time. I don't have personal experience with those but would also recommend testing before you go on holiday as I read some reviews that were great whereas other people said the fish didn't eat them and water quality was affected.
Another option would be get a fish sitter to come in and check on the fish once or twice a week and drop a pinch of food in.
So whatever route you choose, test before you go.
https://www.amazon.com/gp/product/B001F2117I/?tag=ff0d01-20