I currently have an Osprey Stratos 24 daypack that's several years old and weighs over 2 1/2 lbs. I'm looking for something lighter, hopefully around 1 1/2 lb. I want a pack with decent water bottle pockets . One of my big complaints with the Stratos 24 is that the bottles are hard to reach when wearing the pack so that it's simply easier to remove the pack to take them in and out.
I would like something around 20 L for short dayhikes thats comfortable and has at least a couple of compartments for organizing stuff.
I'm a male with about a 21 in torso
Would appreciate any suggestions.

I'm still looking for a lightweight day pack. I find it unpardonable that nearly all day packs weigh more than my overnight backpack!

Unfortunately, there are few daypacks made for short-torsoed (15") women like me. The very few daypacks made for women are all heavy. My hips and Osprey hip belts are incompatible, so that leaves out a big part of the daypack market.

I'm seriously considering a ULA CDT, assuming it can be squashed down enough. Kinda pricey, though.

I looked online at the Ula Cdt pack. The weight is not bad but the overall size of the 54L pack may be a bit bulky for day hikes. It would be nice to try it on but I'm not sure who carries it. If you are interested in it there might be someplace in Portland or Seattle. In Southern Oregon there's not many options. As far as the price, if you find something that really works for you then it would be worth it since it should last several years.
I don't have much in the way of hips so most backpacks with some weight in them tend to slide down unless I cinch the belt to the point where my intestines start screaming for help. With daypacks the issue isn't as bad but as noted in my previous post I almost have to dislocate my shoulder inorder to get the water bottle out of the pocket on most packs.

If you happen to be in Portland, Next Adventure carries ULA packs. They appear to be the only ULA retailer in the Pacific NW, I have the same issues about size, though. I will probably continue to use my backpacking pack, which is about the same size but squishes down quite well.

Have you considered something like this:

https://ultimatedirection.com/pb-adventure-vest-3-0/

Water bottle pocket is on the front strap, so no contortions to get it. It's only 16L, but I'd think that's enough for a day pack. This is a runner's pack, developed (I believe) by Peter Bakwin. Weighs less than 14 oz. If interested, there's someone (not me) selling one for $75.

The HMG Daybreak might work but it's expensive.

Have to been to the Mountain Hardware website? All of their "Outdry" packs are 100% waterproof, which means you won't have to carry a separate waterproof cover you, which is more convenient and saves weight. They are ruggedly built, but also quite lightweight too...Much lighter than most Osprey packs of the same capacity. I have the Scrambler RT35, which I find is perfect for solo weekend hiking and camping trips. It weighs under 1.8 lbs (less than 800 grams) empty. But as you seem to be looking for a smaller pack, somewhere between 20-25 litres capacity, I would suggest their new SummitRocket 20 VestPack. Yes, I know its not an outdry pack, so it's not guaranteed to be waterproof, but it is very light, at just 12oz (340 grams), and they specify that it is "Designed for easy accessibility without removing the pack."...which translates as you would have easy access to your water bottle. In fact, the bottle holder is on the shoulder harness, rather that behind you, on the sides of the pack body, as with most other packs, so access cannot get any easier! Although the price listed on their site is $120, in the UK you can buy it for just £64.99, which converts to a US price of just $88.15, nearly $32 cheaper than the price on their website, so if you shop around you will probably be able to find a cheaper stockist for it on your side of the pond too. https://www.youtube.com/watch?v=JgCd77MW3T4