How to Deal With Players Who Want To Trade Everything?

i agree

I appreciate that.
"When you exchange - have a reason.  Don't exchange without a reason."
That's not bad.
But that reason can be technical and special to the position - or it can be general.  Or anywhere in between.
If a player reasons that many players (or you) aren't comfortable in simplified positions - then that's what he'll look for !  'Reason'.  

Exchanges - captures - checks and so on ...  are Tactical moves.
Have a 'reason' for exchanging ?
If that is valid (it is) - but one should have a reason for not exchanging too. 
That's just as valid. 
Unfortunately - people imagine there's some kind of 'default' that is 'don't exchange if you're not sure'.
That's Invalid  !!
But to each his own.  

One thing that can help is setting clear boundaries for what you’re willing to trade and sticking to them. That way, the trade offers are more likely to stay relevant and not get overwhelming.