Question: Wireless Keyboard Lag?
No question but an answer.
I have a 4th generation iPad running IOS 10.3.3 with a JETech2010 wireless keyboard case. An update caused major lag and connection issues Which drove me nuts. I found that it stopped when I did this: General>Accessability>Key Repeat- I set it to off. This has worked for me (over the past week) but deleting can be a pain because delete moves one spot for every key stroke, same with other buttons. But- key board works. Hopefully it works for you.
iPod shuffle (4th generation, Mid 2015), iOS 10.3.3, Wireless