Adding some dry sacks is a nice idea, but my suggestion is to buy or make a frame sheet.  Every small to medium pack should have one.

I made one for almost all of my packs like this, and the load-carrying capacity is increased a little bit, while the comfort factor is considerably enhanced.  FWIW, frame sheets are made from 1/16" thick black HDPE sheet material, available from Graingers and other vendors.  Once you see how well they work, you will want to make more for other packs.  Remember, no sharp edges, and round all corners.  Use sheet metal scissors/cutters.

That's a pretty good frame sheet, and glad to see you added one to your pack.  I think some folks are skeptical of the benefits of frame sheets, so I was glad to see your comments supporting mine.

@NUJbrown : Have you bent the aluminum stay included in the frame sheet so that it conforms to the shape of your back in the area where the stay is located?

OP, one thing that is possible for you to do, since this is a small pack, is to use some sealant to seal the "sew-throughs" that will admit water into the pack.  This is the stuff, and the foam brush is GTG for a fair while before replacing it: https://www.trailspace.com/gear/gear-aid/tent-sure-tent-floor-sealant/  You want the bottle of the liquid; the foam brushes are ideal applicators, but need frequent replacement.  Search for best price, and shake bottle WELL before using.  Maybe many times.

What I do is turn the pack inside out, and brush a layer of the sealant into anything that looks like a sew-through.  Allow to dry, and turn pack right-side out, and repeat process.  It's important to treat BOTH sides of all sew-throughs.   Use another foam brush for second application.  In the process, seal any loose edges. of fabric or thread ends.  This is an LBT product, so there won't be many.

This process, while tedious, is simple, and will, if done right, prevent a lot of water ingress that occurs because the sew-throughs puncture the waterproof coating of the pack material, and allow water to seep into the pack.  For the price LBT charges, this should have already been done.  This process should be a one-time, permanent fix for the areas so treated

I've done some tests of treated fabric and untreated fabric, simulating heavy rain, running a garden hose downwards on fabric surfaces with lots of PALS webbing sew-throughs, and the treated fabric showed no water ingress through the treated fabric.  OTOH, the untreated fabric clearly showed water seeping through the material through the sew-throughs.

So, water-proofing the pack material has some demonstrable benefits.  This process will NOT fix other water-ingress problems, such as un-flapped/unprotected zippers.  In any event, I urge an application of DWR over the entire surface of the pack.

These fixes will go far in ensuring your pack does not allow unwanted water ingress.

Submitted for your consideration.

Given the volume/weight capacity of the pack, and given that a sternum strap and belly band are included, the suspension system is quite adequate for the pack.  As mentioned above, adding a frame sheet is of considerable benefit, but the pack's suspension is perfectly adequate unless the pack is vastly overloaded, like carrying boxes of ammo or such.  IMHO, that would require a different platform altogether for optimal results.

Your point is a valid one.  My impression is that OP already has the pack, hopefully bought "on sale" which LBT runs from time to time.

However, there is an interesting alternative to very expensive LBT stuff, and that alternative is LBT's offshore-made line, LBX.  https://lbxtactical.com/

These are non-Berry-compliant versions of LBT items.  There is some variance in the features offered between an LBT item and an ostensibly identical LBX item, but the overall quality of the LBX items is very close indeed to the superlative quality of LBT items.

I have one of these packs: https://lbxtactical.com/collections/bkpk/products/0064?variant=13760446005346.  For $110, it's an excellent value.  Add 1-3 Medic pouches for added capacity.  Add a belly-band (3-day pack has one) and a frame sheet (3-day pack lacks one), and one has a far more versatile pack than the  3-Day pack offered by LBT, for a fraction of the price; LBT 3-day pack MSRP is $213.04.  Very similar to LBX pack linked above is the LBT pack here: https://lbtinc.com/collections/packs-and-bags/products/2595d?variant=13213921509419. LBT Price: $376.22.

Submitted for your consideration.