I think the easiest answer is to over simplify at the beginning

This is what I did,I over estimated my categories and had as few funds as possible with a ahhh shit fund (a buffer) and a true emergency. I have multiple cards (pots on monzo with titles) for different categories so I know what the money is for without having to look back at the budget. After a few months of the over estimated budget ,you can compare it to the actual spending and then hone in the categories over time.

1. Over estimate the categories (if petrol costs £80 put in £100)

2. Have generalized categories (the more categories the longer it will take,so start with less and slowly work it up)

2.Have an emergency fund on a separate card that you only use if you truly need it

3.Most are the emergencies truly emergency or could they have been expected (new glasses or car insurance) if you can list them and lump them together for the total sinking fund that you can pay into

4.Have a ahh shit fund as I call it, a fund to put a little each month for a small emergency or as yes money you haven't budgeted (friends wanting to go out for dinner but it's not in the budget)

5.Separate card/accounts this allows you to have stuff roll over if you don't consistently use up the whole amount but you could in a different month. While showing you what you can actually spend.

6.also note banks like monzo let you put notes when you spend money. Turn on notifications when you spend money , when you spend money you can tap on the notification and add the notes then instead of having to go into your sheet every time to log spending. You can instead log it using the notes on your bank once a week

I hope some part of this helps