Need advice for Sendra Boots sizing

Hi everyone!

I've had a pair of biker boots for a while but I find them a bit too wide at the top of the shaft where the gap is almost 2 inches. I know it's quite normal but I usually wear them over slim jeans like levi's 511 - 512 so I'd like a slightly more fitted cut at the shaft.

So I looked at different brands and in my budget I thought of getting Sendras style 1918 Pete, 2621 Pete or 8833 Blues.

But I'm not sure what to expect in terms of sizing, especially since I can only buy them online, so I'd like your opinion. In sneakers size I'm 44 EU and I have quite narrow feets. From what I've read, in general for square-toed boots, people recommend taking a size down from your sneaker size, so in my case it would be 43 EU.

What do you think of all this (size of the shaft, general sizing etc...) and do you have any advice?