Is my phone encrypted with my password?
You device is encrypted, but PIN is used for unlocking master key.

From

I set up a password, and select to require password at boot. I then set up a PIN for unlocking the screen, but did not select to require PIN at boot.

we can assume that you wanted different lock screen &amp;&amp; encryption passwords.

Because you are using LineageOS, acquiring root for ADB is not issue.

For achieving what you presumably intended 1st define lock screen password or PIN - select Require password/PIN to start device. Lock device &amp;&amp; do a power cycle - not every1 will agree with this procedure, but I tend to verify.

After successful bootstrap, for different encryption password you should either change password via ADB or terminal or purpose built application - 
SnooperStopper or Cryptfs password manager

If you preffer ADB or terminal, while in shell, issue

adb root && sleep 2 && adb shell "vdc cryptfs changepw password [curent PIN/password] [new password]"

and hit return; if terminal is only option for you, issue only vdc cryptfs changepw password [curent PIN/password] [new password]

You should always verify PW with

vdc cryptfs verifypw [PIN/password]