over a long time of tests I have discovered that the cookies are save to my computer regardless to accept or reject cookies at entrance with a button. I have tested many web pages. Some web sites offer to reject cookies, some don't. Once I rejected the cookies, the cookies were saved to my computer. Once I deleted the cookies immediately from my computer, mostly the web pages worked without problems. Some web sites like Microsoft.com downloads cookies continuously regardless I rejected the cookies.
I have tested Microsoft's Teams. I registered to a conference and waited 20 minutes for invitation to the room. Over twenty minutes of no activity Microsoft stored on my computer 46.1 Mbyte cookies.
I have looked over the net for cookies source codes to get information what of data the cookies collect. Nothing was found. On the other hand, I know, that cookies collecting the data from computer of web site visitor and send the data to unknown server.