What if I don’t have a Mac to connect my iPhone to? Can I not update it manually in settings or connect to a Microsoft computer to update my phone?

Yes, you can update over the air (OTA).

Make sure :

• iPhone is plugged in to wall power
• iPhone has Internet connection via Wi-Fi
• iPhone has enough free space (<> 4-5 GB)

Or connect iPhone to your Windows iTunes app and update from there.

Read here => Update your iPhone, iPad, or iPod touch - Apple Support

You do not need a Mac. And if necessary you could use a Windows PC to update your phone.

In fact, you do not even need a computer to update your phone.

Hopefully this link puts you on the right track

Update your iPhone, iPad, or iPod touch - Apple Support