I do toasties rather than sandwiches as bread can be quite claggy for them to eat!
I agree with the comments above. I found sandwiches a hard one. Mine is 2yrs and few months and still not keen on sandwiches. At 9momths I used toasted bread and deconstructed sandwiches as above. Later on I used wraps and she found those better (although most times she ended up deconstructing them too 🤣
A full sandwich is pretty hard even past 1 year. Deconstructed is usually best as it gives them the ability to feel all the different textures to work out. Or if wanting to do something like PB&J only a single slice of bread open faced.