With the exception of safety-related things, I think there is usually no right or wrong way of doing things - just look at how often guidelines change (as a previous poster said).
I hate all these buzz words and phrases like "breast is best", "baby-led-weaning" and "tummy time"... The whole tummy time thing in general actually. Both my girls absolutely hated it, so I didn't push it. And guess what, they have developed absolutely fine.
I cannot stand baby showers, I find them really tacky. I also think there are far too many "classes" and pressure to be doing activities every day with very young children, especially those under 1.
Screen time is fine in moderation and depending on the content. There are some amazing YouTubers we discovered during lockdown that taught my toddlers so much. Some of them are qualified speech and language therapists etc, and I don't think you could get much better if you paid for a session.
I also try not to stress about what my toddlers eat. I like to give them a variety of food with plenty of healthy options, and it's up to them what they eat. I think that making a big deal about it is only going to make them more fussy. If they're getting their daily vitamins and are generally healthy and happy, they're fine.
Probably my most controversial opinion is that very young children should be looked after by a parent or other close family member, rather than put in childcare (I know, many people don't have the option. I just think that's the ideal for the child). The thought of leaving my babies with a stranger before they can even communicate properly makes me shudder.