The Americans use a fiixed spool often for big fish like Tarpon over 100 lbs with no problems. The fight from these Far exceeds any pressure we would put on a reel for general fishing from a boat in this country.
Pump and wind is what it is all about to reduce stress on the components parts of any reel type you care to use, on any fish that pulls back or is hauled up from any depth.
If yuo go to my original post so will see I mention "Our style of fishing" or words to that effect.
Huge free running fish can be taken on fisxed spools and pumping and winding is the answer.
A fixed spoole is also fine for some styles of UK fishing such as "light" pirk casting and some uptiding.
Where they have a problem is when we need to use lots of lead or where large clumps of weed can be expected in "fast" tide runs.
In situations like this, pump and wind doesn't work a jot. You lift the rod and then go to lower it winding at the same time, but with 2lb of lead or even 12oz of lead simply dropping too with gravity it is simply very awkward and uncomfortable.
Just my opinion, but those of us who have the gear to do it, run your own test.
Using two identical rods fished with the same baits at the same time requiring
12oz or so of lead. Use a mangle on one and a reasonable quality multiplier on the other and see which one is more comfortable.
There is no doubt, a fixed spool reel is quite capable of playing large fish, but they are not suitable for winching. and there are times in UK angling where we do have to winch.
(Afishionado, tell me that you'd be able to fish the "Sky" for Conger. Even on a neap, once the tide is moving you need 2lb here).
Tom