Marx eventually settled on the position that it is not the conditions per se but the mechanisms that lead to them that are the issue, as they will always lead to the same fundamental problems. Which is the case - an IT worker has the same fundamental conflicts as a factory worker. At a certain level, losing these conflicts despite nominally better conditions doesn't necessarily lead to better outcomes.

If Marx was still alive today, I think that he would answer the question about how modern workers have such better conditions than those in early capitalism the exact same way as when people in his time said that proletarian had better conditions than the peasants before them, which was nominally true.

In any case, the prescriptions of how a 19th century proletarian could improve their life are essentially the same. The idea is that the interests of your employer will always he opposite yours, as a result you will only be able to improve your conditions by organizing with your fellow workers in order to tip the balance of power, and eventually it is in your interests to change the conditions that lead to this conflict to begin with.