Sounds good. One thing that should be considered is armor. But probably counts as 1 for +1 Ac, 4 for +4, etc., or even twice that much.
Here is my system, from Dark Fantasy Basic*,FWIW.
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Most of the time, the weight a character is carrying can
be ignored unless it is metal armor, bulky or numerous
items, or any heavy burden. If this is the case, the GM
might assign consequences based on common sense, or
use the rules below.
A character can carry a number of items (or units of
weight) equal to his or her Strength score before being
slowed down. Additional items will cause speed to drop
and hinder various activities.
Disadvantage applies to several skills, including Spellcasting,
Athletics, most uses of Thievery and any time it would make
sense. Penalties apply to those and also to AC and Combat.
Some activities will be impossible when encumbered (GM’s
call).
Example: a PC with Strength 12 can carry 11 items with no
problems, 12 or more items with ¾ speed, etc. Carrying
24 items or more will cause him to get disadvantage and
a -2 penalty to his stealth checks, but only a -2 penalty to
his attacks and AC. Carrying 48 units will stop him from
walking.
Equipment weight
A standard “item” weights up to three pounds; examples
are one-handed weapons such as sword or mace (with belt,
scabbard, etc.), a winter blanket, climbing gear, a backpack,
a grappling hook, 40’ of rope, 20’ of chain, clothes, a toolkit
(for hiking, healing, disguising, fishing, or other specific
purpose), a bedroll, an iron pot, and so on.
Heavy items such as two-handed weapons, 10 foot poles, a
shovel, winter clothing, etc., count as two or three items (or
more, depending on the case – see the equipment section).
A thirty-pound sack will count as ten items, for example.
Armor weights 3 items per point of AC. Shields are lighter:
2 items per point of AC (if you’re using more than one type).
Small things may be bundled together and count as one
single item (for example, three knifes, 30 arrows, 1000
coins). Things that fit in the palm of your hand usually
count as small items.
Weight Carried / Speed / Penalty
Less than Strength 100% -
Strength or more 3/4 Disadvantage
Strength x2 1/2 Disadvantage, -2
Strength x3 1/4 Disadvantage, -3
Strength x4 0 Disadvantage, -4
A PC without equipment weights an average of 35 units plus
Strength score.
Movement
Most characters move 120’ for each 10 minutes while
exploring unknown, dangerous locations such as dark
dungeons. Triple that speed for outdoor environments.
During combat or chase, a PC can move up to 40’ per round
(240’ per minute). Hiking speed is 24 miles per day (walking
8 hours per day), but see the Wilderness section for difficult
terrain. Climbing, crawling, swimming, and sneaking around
halves speed (or worse) for the duration of the activity.
Consider an ordinary mule ($30) or horse ($40) to have
Strength 40 for encumbrance purposes. A warhorse ($200)
will ride into battle. Mules and horses with Strength 60 are
also available (triple the price). Base speed is the same as
human.
Horses can double their speed for up to eight hours.
Humanoids and mules can add 50% to daily speed by
marching for up to 12 hours in a day. In all cases, they suffer
exhaustion by the end of the day (see the Hazards section).
Likewise, a character can triple his combat speed for 5
minutes, but must immediately rest for half an hour after
that, or suffer exhaustion.
*https://www.drivethrurpg.com/product/229046/Dark-Fantasy-Basic--Players-Guide