Dishwasher + washing machine connected to a hot water supply?

Hello, I did some reading on this topic today. Until now, I was convinced that both the dishwasher and the washing machine should be connected to the hot water supply. Now, after studying various magazines and internet forums, I have changed my mind. With the washing machine, the problem is that you only need hot water during the first wash cycle, not during rinsing, etc. So a bypass device would be necessary, which costs around 300 euros. Various fabrics like wool are also washed with cold water. The same applies to the dishwasher. Since it uses very little water, it’s not worth it. Also, for example, protein residues require rather cold wash water than hot. Additionally, it would be better for the dishes, as there would be no temperature shock. What do you think? Leave it as is or not?