NON-EU Applying to ILR

Hello Everyone !
I am married with EU citizen and from 01-03-2016 we are living in UK. I have some questions about ILR slowly slowly I want to prepare for the application.
I am not sure how the 28 days is working. Is it from when you are entered the UK ? If it is when do I have right to apply ILR ? Also I lost my Resident Card that I have got first time and I did applied one more time and get it that time I asked the person from HO and they told me 5 years count from the time I enter the country and I am assuming 28 days counting from before 01-03 for me ? Because my current Resident card expires 2023. Another question is based on Brexit me and my wife have to apply for pre-settled status. Based on our enterance to UK should we wait

-The deadline for applications will be 30 June 2021 – or alternatively the earlier date of 31 December 2020 should the UK leave the EU without a deal.
or doesn't matter anyway ?
The questions probably asked millions of times before and I am sorry for asking again !

Also when I apply ILR and if I use one of the premium services and get my ILR, after when exactly i can apply to citizenship ?

There is no "28 days" rule for eea route settlement etc. You need the full 5 years residence for ILR settled status, counted from the date you entered the UK as an EU or eea family member.

You have to hold ILR for 12 months before you can apply for citizenship. The only time this is not required is if you are married to a British citizen.

Alright so 01-03-2021 is the date I will apply and until then we have to apply for pre-settled status, and then I am assuming we will apply for settled status.

I was thinking to wait for the decision of Brexit and I might be applying to settled status straight.
-The deadline for applications will be 30 June 2021 – or alternatively the earlier date of 31 December 2020 should the UK leave the EU without a deal.

If not I will apply pre-settled anyway before 31-december 2020.

01-03-2016-01-03-2021