I have a 2018 SCOTT Spark RC 900 WC that weighs about 10.80 kg, just under 24 pounds on race day. I’ve upgraded with AXS shifter/derailleur, Quarq XX1 power meter, Eggbeater 11 pedals, WTB Volt carbon saddle, 9point8 Fall Line R dropper, and Light Bicycle carbon wheels (~1400 grams for the pair). I don’t skimp on tires so I have Mezcals 2.35 f/r that weight 705 grams each.
All that being said and it was certainly fun chasing grams, I’ve learned through my racing that it’s likely to make almost no difference on race day. I’ve been beaten by guys on bikes that weigh 5 pounds more than mine and are carrying an extra 20 pounds of body weight. What has made a big difference is consistent training following Base - Build - Specialty of TR and regular mental training (Headspace).
If you have money to burn, the wheels are a great place to start, just realize it is a marginal gain at best and there are free low hanging fruit.