Experience as an HCA will not damage your application for medicine. Indeed when reflected on properly is likely to enhance it.
To be honest though I am not sure that the apprenticeship part would be ideal.
This is just my personal view but the apprenticeship programme and HCA / social care workforce is under so much pressure that taking an apprenticeship spot from somebody who might need the job and continue in it as a career seems a bit off.
If this was the only way in for you then I guess, but apart from my reservations on the point above, there are just so many HCA/care jobs in nursing homes available out there with no experience needed that thereb is just no need to take an apprenticeship slot.
If doing it that way look for a vacancy in a care home providing nursing care ideally, not just social care. This will provide more opportunities for medical reflection. A care home will provide a lot of opportunities for caring which is also very important for your application.
Both will support you to undertake training if you wish.
HCAs/care workers are not paid as much as they deserve. But they are paid a lot more than an apprentice HCa/care worker if that matters to you.
Good luck with your gap year, making it a productive one is the most important thing imo and it sounds like yours will be.