Research has shown (many times) that babies aren’t habit forming up till 8 weeks (and in plenty of cases, a few weeks beyond). The trick is doing whatever it takes to keep them happy until they’re around 12 weeks at which point you should recognise what works for them and you which can evolve into a routine.
Interestingly, nobody ever posts “I tried Gina Ford and it was bollocks” which suggests of course a big stinking pile of confirmation bias. Anecdotally, I’ve seen the book gathering dust on the shelves of some friends who aren’t getting any sleep 9-12 months into it. The only thing I’d ever advise regarding sleep routines, is to keep the bedtime routine post say 6pm pretty regular and relaxing.
Babies are different and some are better sleepers than others. I was given a brief insight into having one that doesn’t for a week with teething and a virus. It was a shit week and emphasised that nobody likes a Smug McSmuggins. 🙂