I’m also going to be frank here.
You just can’t consistently plan lessons in 5 minutes around a TES sheet.
Glad this was said. I used to pour most of my time into creating really good resources.
But, yes, in the first years of teaching it is all consuming. You work long days and weekends.
After a while, you should have built up a bank of really effective resources so that year on year you only need to tweak them. Yes, there will be other things to master, but the resources should be ok.
However, the workload in some schools is crippling. I left teaching last year because I knew it would make me ill. I was being micro-managed by a HoD far less talented than me, in a really toxic environment generally, and I had to just get out. I am now re-training.
Tips from an old-timer:
Get displays set up before term starts, then all you have to do is add good work as it comes in.
Look at the pinch points for the term/year in advance (usually around assessments) and clear your diary for those weeks. You'll be in early and home late just to keep your head above water.
Be ruthless in establishing a calm and orderly classroom, otherwise you'll waste hours of every term dealing with pointless and demoralising behaviour issues.
The rest of the time, work with ruthless efficiency to get planning and marking done in school hours. Don't chat to colleagues during lunch breaks. Avoid unnecessary meetings. After assessments, plan lessons which require minimal teaching/intervention from you so you can mark the assessments.
Remember that formative feedback is more meaningful than summative, but it can be delivered to the whole of the class, and they write targets based on your verbal feedback. See also self and peer assessment for useful marking techniques.
Make use of digital resources where you can, to avoid photocopying.
Create a bank of comments for reports and assessments, and tweak for different students. Cut and paste, but be vigilant in not making silly errors.
Contact parents early with concerns. Use the heads of year or other pastoral colleagues to ensure you don't lose control of behaviour.
Have fun in your spare time. A rested teacher with an interesting life will always be better than the jobsworths.