You could always try on another machine if you can to see if the latency is due to the laptop or the keyboard itself.
Also, changing keyboard, especially if you’ve been using a certain keyboard type and you change to another, can really mess uo the eay you type until you get used to it.
Lastly, bluetooth is a whole mess so it very well could be that. If you value what you bought and like you said, someone close to you is a tinkerer, converting a bluetooth device to a wired can be a nice project if they haven’t done so before (and it prevents throwing out a working device with a small defect).