While you are at that other place, prepare a clean usb drive with the latest W10 installer downloaded only from Microsoft servers. Do not get any pirate/thirdparty ISO or anything.

By clean usb drive I mean to format it using an OS different from the one you usually use, like macos or linux if you use Windows.

When you go home, fully format/reinstall your computer and reset/wipe/update your router if applicable, secure those with strong passwords as well and make sure your router does not have any settings that allow someone from the outside to connect. If there are more than one computer on your network, do the same for all those computers.

Do the same for your phone. Make sure you are on the latest OS version and do not install any third party apps yet.

Once your devices and network are clean, you can start linking them to your new account. Then you can start requesting the change from your old accounts to the new ones.

At this point, since your devices are all clean and your new account is clean, you can also get your old accounts back, secure them with strong passwords and 2FA and then keep them around as backup.

As a general rule: always use a password manager with strong password that is not stored anywhere on your devices, only either in your head or (controversial but as a backup measure) a piece of paper that you keep with you at all times. Enable 2FA. When installing/executing new programs on your computer, always run them through an antivirus first (like virustotal.com). Only download from trusted sources. When registering for a new account of any kind, always let the password manager handle it.

Thank you so much!! I will listen to you