Death March kara Hajimaru Isekai Kyusoukyoku (WN) - Book 11 - SS: Practice Scene

This is a therapeutic romance novel that mixes psychology and science fiction.

Amamiya Hiroto is unlucky. His life consisted of misfortune after misfortune, culminating in an unlucky death during an incident on a school boat trip, trying to save a girl he barely knew. After death, he met a god of reincarnation who requested that the hundred or so dead passengers—one of them being the girl he tried in vain to save—be reincarnated into another world.

Jiang Pengji got something called the Court Intrigue Stream System.
System: “Your goal is to become the most prestigious woman in the kingdom (the Queen)!”
Jiang Pengji: “Okay, System. No problem!”
Years later, she met the target by becoming the most prestigious woman (the Empress).
Jiang Pengji: “Well done, no?”

- Description from Novelupdates

Jian Chen, the publicly recognized number one expert of the Jianghu. His skill with the sword went beyond perfection and was undefeatable in battle, After a battle with the exceptional expert Dugu Qiubai who had gone missing over a hundred years ago, Jian Chen succumbed to his injuries and died.

After death, Jian Chen’s spirit was transmigrated into a completely foreign world. Following an extremely fast growth, his enemies piled up one after another before becoming gravely injured once more.

On the gates of death, his spirit had mutated, and from that moment henceforth, he would tread on a completely different path of the art of the sword to become the sword god of his generation.

- Description from novelupdates