Indeed. I guess it makes sense to think about home if you live in Europe, as I think you do, and I do too! Vast majority of folks on here come from USA and spent $000s on doing a Camino and plan for ages so agree they should not throw it all on for flu or Covid unless it, or other things, are serious. Getting ill a long way from home is a mental strain too so I guess it’s a tough balance.
I have the luxury, as you say, of not living a million miles away from home.
I have also done a public hospital in Spain (in Santiago) while suffering anaphylaxis and it was interesting and eye opening. After a while of attempting to be able to breathe, while waiting to be seen, I used a bunch of epipens and that lowered the initial problem to something manageable (although it did cause the hospital staff to start freaking out). After some hours they put me on a ward and that was not good on many levels, it was really busy and I don't do hospitals generally due to ASD, they push my stress levels way to high.
So for anaphylaxis I can probably tolerate six hours in hospital, but they were really arsey about letting me go (I have allergies, I deal with them myself a lot and once they confirmed by blood test it was an allergy I had everything meds wise to treat it) and in the end I was on the verge of calling the British embassy at which point a doctor said I could go. I honestly found the experience really hard and went off to the campsite (As Cancelas) in Santiago and pitched for a couple of days away from people to decompress and calm down.
Flying back for me is more for bad acute problems, broken arm, maybe my asthma went downhill massively or some other annoying problem. I've learn't over the years it's easier to bail out to somewhere familiar and deal with the problem, than try and push through. That familiar place isn't necessarily home, it could just be my tent or a hotel. Use common sense and you'll be fine.
If you have flown from the US or Asia, then my advice would be to book an airbnb, or room in a hotel. If the problem is just some light Covid or Flu, you can probably get through it in a week and if you are of good health it probably won't have much impact on you. The main problem comes if you aren't of good health.
As for the food, if the problem isn't debilitating, hit up a supermarket and stock up on easy foods, even if they are just bars of chocolate, muesli bars, cereal, milk, bags of salad, bottles of water. If you have a bath/sink, fill it with cold water, drop your chilled goods in, it will give you a day or two. Have enough for 2-3 days. Then hunker down, sleep as much as possible, push through.
If it is debilitating (broken leg, etc), you will have to rely on others. I would probably open a thread on here and ask if anyone coming through could grab you some food and drop it at your hotel. People are generally kind and open to helping other pilgrims, so I think if anyone is in the area, they might drop you some supplies. As mentioned, the locals will also generally offer help, if they can. If you have a broken leg or similar, it's game over, arrange your flights. With a 6 week wait to gain minimal use and possibly a year to recover full function, your camino is over on that session.