Right. And if he wanted that to happen, Harris would be convinced, and she'd announce that she is retiring to spend more time with her family.
But more likely he would just run with a new VP.
During the Nixon presidency, when his VP resigned due to pending criminal charges, Nixon consulted with the House and they came back with Ford, a moderate. If Biden was interested in going the same route, he could give the House a list of say five democrats he would consider, then let the House choose the most conservative of them, thus giving the House a "victory" they could tout and ensuring a more moderate VP. Or just run a new person on the ticket.
For example, consider a Biden/Manchin ticket. That would turn off some democrats, but would likely energize a lot more independents. And even a few conservatives; if a lot of conservatives think that Biden is going to die in office, they might greatly prefer Manchin over Harris if the alternative was Trump.
Or consider a Biden/Sinema ticket. That would get more democratic support and likely a LOT more independent support. Heck, if Harris was convinced to retire, the house would probably approve replacing her mid-term.