As the grade of fish gets bigger, the [comparatively] lighter tackle choices of a few years ago become insufficient.
Up until 2020, a Fathom FTH40NLD2-size reel filled with 80 pound braid would easily handle tuna up to 150 pounds, and give you a fighting chance on fish to a bit over 200.
Suddenly 300 pounders became a real possibility on almost any trip, and 400 pounders were proven to be out there.
A fundamental choice becomes necessary as you step-up from the "medium frame" reels.
At minimum these days, an International 16VISX reel filled with 100-pound braid has become "don't leave the dock without it", and can handle 300-plus pounders. One "loaner" 16VISX that lives onboard the Pacifica caught three over 300 this season [biggest 353], though the line capacity will get a bit skinny when encountering those supercow-grade fish.
The 40N-size reels weigh about 27 ounces, and stepping up to a 16VISX moves a bit to 36 ounces.
The larger 20VISX/30VISX models that many anglers are starting to go with are around 51-53 ounces, but in addition to greater line capacity, offer bigger gears, bigger drag surface, better heat dissipation, etc, etc, so you have to decide if the additional weight is justified.