Which fitness tracker/device in my case?

Tatarataa

Hey guys,
I need some advice on which fitness tracker/device would be the best for my needs. I am a stay at home mum who tries to incorporate as much activity as possible into her daily rountine (and therefore it can vary a lot how much I can do depending on my tots needs and moods...). So you will find me walking in place and jogging in place, doing home exercise videos like Leslie Sansone or home biking on a sitting bike at low pace while surfing the web when the little one sleeps, walking the mall, trying to walk faster when doing grocery shopping, increasing my load by carrying the little one in the carrier while slowly walking, doing side step movements at home, trying to dance for a couple of minutes or doing some exercises from youtube...and also hitting the gym, mostly for some machine strength training and water exercise (all kinds of, mainly deepwater, some aqua jogging, some aqua hit, sometimes more aqua strength training), and every now and then I enjoy hiking (mostly on flat terrain due to the area we are living in). Every now and then I manage to go out for a run.

I heard that many activity devices have trouble with monitoring certain kinds of activity (like some fitbits or pedometers have problems with sidewards steps or heartratemonitors cannot acurately measure strength training, and for water exercise it seems to be difficult to find any device....).....

Which device would you recommend me? A pedometer? Which kind of fitbit? Or just a heart rate monitor and if so which one? Or none at all? Note I would rather have something that underestimates than something that overestimates...or if you would recommend something that overestimates please also give me some advice on how to use it to lose weight (like not eat all activity calories back).

10000 times thanks in advance for any advice! I feel a bit lost concerning this and as it makes a big part of the caloric equation any advice woule be helpful! Also, I am not na very technically person, so the simpler the device to use the better I guess...