Hello !
I own a Honda and an R65. The Honda is a CBF600SA6. So same volume/weight as the BMW.
With the wheel bearings properly greased, I see no discernible difference when moving either bike. But I must confess that the BMW had suffered a very lazy maintenance and care for more years than I care to mention. So the bike was stiff really stiff. The handlebar was hard to turn and so on. Last year I decided to do something to her and started to put things back in order. New grease on every bearing I had on the bike, new fluids, carbs clean-up and rubber renewal, etc. ...
Wow ! It makes a tremendous difference. The bike, now is smoother than the Honda... So maybe part of your problem lies here. Add some drag on the brakes and you've a square rock to move around...
Last but not least, how to mount/dismount the bike ... I have no problem being more than 1m85 high. But my wife is 1m50. So small. But clever. Se mount the bike by putting one foot on the foot rest, climbing it, then passing her leg over the bike. Apply the reverse to dismount.
I told this to a friend which is smaller than me when he bought a 1200 GS with which he has the same problem than yours. He bless my wife every time he sees her... So give it a try. (let the bike on the lateral stand while doing this)
Hope this helps.