I also used one for a while - tried to alternate the use of it with my current LO, but also previously fed 2wks solid with them for the older child as they were premature and the mouth was too small for latching. I didn't massively struggle to get weaned off the use of them entirely, but my only suggestion is to start a feed with the shield and then maybe after 4/5mins or so take baby off, remove shield and then try again without. This way baby is not trying to latch whilst starving and so they are less likely to be fussy and difficult...only a suggestion, but hopefully it might help! Good luck
I used shields in the first weeks (first 2 months??) mostly because my nipples were super sore and that it made the latch easier. Now baby is 8mo, still breastfeeding, and we don't use them anymore. You can change the nursing position to "play against" gravity if your flow is too fast. I can only recommend to visit a lactation consultant for personalised advice. 😊
I was able to wean off as I started using one due to a number of problems. I wanted off around 3 months maybe a little longer. Feel free to message me if you want to chat!