Random weird question

I really don't know what topic this should go under but here we are.

I'm going to try to make this as clear as possible and I know I can Google or call the SS office but I'm asking here incase anyone knows

Okay so I'm trying to figure this out for someone close to me but I'll just say "me"to make it quicker & shorter.

Say you got married in 2020 (spouse last name is on marriage certificate) but never changed your last name legally at the social security office. When/if deciding to finally go change..would it be updated/marked to married from the actual wedding date or from the day I go in? If that makes sense. (Nothing has been changed to spouses last name...ID, bills, accounts, credit cards etc all still in maiden name)

For example- the IRS. Say you filed single/HOH since being married (bad/wrong I know..example & not the point lol) and your spouse filed the same way (not married-diff addy or whatever) anyways...say you go change the last name and for next tax season you file married/married but separate and on the screen it says "date of marriage"...would you put the date you went to change your last name officially in 2022 or the wedding date in 2020? If you put 2022 would they be able to see the day the actual marriage certificate was filed in 2020 after the wedding? I hope I'm making sense. As of now, when taxes are filed the IRS does not know of the married status since it was never filed with social security...and that's a fact.

I hope that was clear enough to make sense.