Bed. That is the "luxury" you should prioritise above anything else.

I've slept in all kinds of qualities of bed (and discussed it with others who have done the same.)

The quality of the bed you sleep in at night is a huge factor in the quality of the you that you are when you're awake. The best sleep I've had on bad beds is still no better than the worst I've had on good ones and when you repeat that day after day, into week after week, into year after year, the cumulative effect on both your quality of life and physical health is immense. You should never make sleeping on a bad bed your long-term plan if you can possibly avoid it.

Every single day of your life is influenced by the quality of sleep you got before you started and therefore the quality and type of bed.

It is a huge gap in privilege between people who have lifestyles that make a good bed a standard expectation that is easily achieved and those who have to make do with what's cheap. The former group will always just be healthier, happier, better rested and more prepared for the challenges in front of them than the other.

I'd recommend a good quality pocket-sprung mattress (you can't really find cheap bad ones) over a sturdy wooden slatted frame although the modern foam mattresses are also very popular now and can be a good choice if you can't easily realistically get a massive heavy inflexible mattress where it needs to go.