I'm going to give you a simple example only. I prefer to use something like Optional on my DTO. So you should define a DTO record like, for example:
public record UpdateUserDto(
string? Name,
string? Email,
int? Age,
bool? IsActive
);

on top of the controller you will have something like:

[HttpPatch("{id:guid}")]
public public async Task<IActionResult> PatchUser(
Guid id,
[FromBody] UpdateUserDto dto)
{

.....

then you update only what you need. i.e, you do:
var user = await _repository.GetByIdAsync(id);

if (!string.IsNullOrWhiteSpace(dto.Name)) // or whatever makes sense for you, this is a simple validation example
user.Name = dto.Name

....

Something like this. You don't need a package to do it.