Trouble logging into Desktop on MacBook Air, please help

Recently, I had A LOT of trouble trying to login to my desktop on my MacBook Air because I forgot my password. I finally was able to enter the recovery key and then change the password which opens the desktop. NOW, I am unable to see any of my passwords so I thought if I use iCloud to sync the keychain /passwords this would fix the problem. This would not work because when prompted to enter the new login password, it then asks for the password to the former MacBook Air which is totally wrong because I only have one MacBook Air. Needless to say, EVERYTHING IS MESSED UP and now I have no passwords and both my iPhone and MacBook show messages prompting me to update the settings BUT THEY DO NOT WORK ON BOTH DEVICES WHEN I ENTER THE REQUIRED PASSWORDS. HELP, PLEASE! THIS IS A TOTAL NIGHTMARE AND GETTING HELP AFTER 7:00 PM PST ON THE PHONE IS IMPOSSIBLE. Ever since Apple started this sharing device info I have had serious issues. I don’t like my devices to share any data with each other except passwords. NOW I HAVE DUPLICATE OF EVERYTHING ON ALL 3 OF MY APPLE PRODUCTS - WASTING SPACE AND ICLOUD STORAGE! THIS SUCKS!

[Re-Titled by Moderator]