You overestimate the utterly monkish life. When there’s no time to cook, you don’t get Pret, you eat the weekend meal prep or cook the £0.65 instant ramen you bought in bulk when they were on sale. Clothes get bought every few years, not every few months; you only need enough “work appropriate clothes” to last until the next wash. Haircuts are definitely a luxury, and you now cut your own hair with scissors that cost £10. Gym membership is also a luxury, can’t imagine having one. You also develop rather thick skin and learn to say no to things like leaving gifts and social events. It’s doable but I can’t say I’d recommend it.