That is YOUR opinion. I try to avoid adding KPS to my own AWs. No real need to either, I rather spend all my KPs on the AWs of other players so I get more returns.
And there is no 'negative effect' on donating more than the maximum chest. In the end the swaps are swaps, so every point I invest in someone else's AW will come back through the chains, so you always end up getting at least as much as you gave. Everything gained from chests earned is just extra. Not 'winning' 100 extra KPs does not equate a loss.
If I invest 600 KPs and get back 600, it's neither a loss nor a gain. If I invest 600 KPs and get back something from a chest it is a positive effect.
The only way to have a 'loss' is if you donate randomly without getting anything back at all. And even that is debatable; it does generate extra room for you so you won't get KP-locked as easily which for some people might be a gain in itself.
That I actually do agree on. It is much better to work 1 AW at a time as having several half filled AWs don't give extra benefits, but 1 finished one does as soon as it is upgraded.
As for chains being clumsy; maybe that is your experience. Sadly, that means you only have had some badly organized/supervised chains. We use our chains often, intensely and at a high pace and everyone who does benefits from that. Whether they participate or not is up to them. But the ones that don't have their AWs generally at (much) lower levels than the ones that do. Which is a choice.
Right now I'm sitting on this, a bit over 19.000 KPs in instants. and that's not counting any runes I can use, or the regular KPs from collections, Wonders, Evolving buildings, events or tourney.
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So I could use all that on my own AWs, but that means zero return. That actually is a loss. So instead I spend it on the chains, or on AWs on players on my map that are almost finished and have open chests up for grabs (which usually are players who invest only in their own AWs and have no others contributing).
Or I can use your suggestion; that means that without a doubt I will be the one grabbing all the top-gold chests from everyone in my FS as nobody will come even close to this. And because of that, I'd only be getting more and more and nobody would ever be able to outdo that.
With the chains, anyone can end up being the one to grab the top chest.