I have an adjustable quill stem on my cannondale and love it except for one thing.
It tends to loosen up every so often. NO big deal, but it's annoying and doesn't inspire confidence.
It's a trans-x tool free adjustable quill.
I love it because I can start out with the bars lowered in a more aggressive (relatively speaking) posture,
then if that gets tiring I can just pull off to the side and in 30 seconds or so raise the handlebars and finish the ride in upright comfort.
My question is related to regular bolt on adjustable stems that require a tool to adjust.
Do they also come loose or does the tool requirement keep it more secure.

I have a basic stem extender on my Giant. Sorry I don't remember the brand but I would be happy to check. It has a 2 3/4" range of adjustment. It uses two large allen screws to secure it to the existing stem and two smaller allen screws to adjust the height.

A stem that loosens up is a big deal to me and I would instantly change that part.

If all you want to do is easily raise and lower your stem, you can try one of these for aheadset NVO COMPONENTS - SPACER FREE STEMS | SPACER FREE STEMS

or use a quill stem if threaded

The advantage of this over adjustable angle stem is that they use fewer bolts, and there are less adjustments to be made (hbar angle, headset preload)

Does it stay secure?

This is the one I have. It stays VERY secure.

I have personally never had the desire to adjust the stem when out riding, but if I did, I would get one that required tools to adjust, and take the time to get a solid adjustment.

I don't know how they would deal with constant changes, but I rode a few thousand miles with the stock adjustable stem on my 2013 Giant Sedona DX and it never slipped.

I would personally get a rigid stem that would get your handlebar at the right position (possibly half way between your two adjustment points, and keep it there and/or adjust height by loosening and tightening the quill bolt.

I have an ITM made 'CNC' angle adjustable stem, 11 years it has been just fine.

On today's bikes with threadless stems, one can install a stem riser and put the stock stem on it. That will usually suffice to raise the stock stem to a comfortable riding position.

I don't like these kind of 'fixes'...Stem risers may be fine, but in my experience sticking with the components as designed by the manufacturer is usually the safest
and most reliable way to go.

If the stock stem is raised to maximum, it still may not be high enough to reach the bars comfortably. A stem riser raises the height by 3" which is usually sufficient to raise the stem up to where it needs to be.

A stock setup may mean bars are set too low and then you suffer from a bad back, strained neck and other ailments. There is nothing wrong with customizing your bike to fit you, your physique and unique riding needs.