New wheels

I’ve been told the best upgrade for a road bike is new wheels so was wondering if there was anything worth looking at in the UK sales.

I’ve got a Trek Emonda SL6 from 2018 with “Bontrager’s mid-range alloy Paradigm” with disc brakes, so need something noticeability better to justify spending the cash.

I’m looking for tubeless and have up to about £500/wheel. Not looking for deep set, they are going to be used for training and (fingers crossed), two Ironman races later this year.

Anyone got sales suggestions?