If you want to replace the two strp ladders because of weight or convenience, maybe try the Hailo step ladders, which are usually fairly lightweight, but in many cases, still rated for 300lbs.
Apparently Hailo now makes a step ladder with extendable legs so it can serve as a 3, 4, or 5 stepped ladder. (I have no experience with this).
The aluminum telescopic stepladder with a flexible working height.
www.hailo.us
The regular ladders are pretty good as well.
HAILO L100 TopLine | Aluminum safety household ladder | 4-8 steps ✓ Safety & comfort at the highest level ✓ Top quality ✓ Direct from the manufacturer
www.hailo.us
Depending on the number of steps, the weight usually runs between 10-22lbs per ladder.
Aa for the Little Giant Multipurpose ladders and clones, I would probably recommend fiberglass, since it gives the extra electrical safety.
(Werner’s version is usually less expensive than the Little Giant fiberglass version).
One thing about Little Giant ladders, is while that pack up shorter than regular ladders, the actual ladders are otherwise bulky and heavy.