Staying more than 450 days out of the uk

I have had a no time limit residency in the UK since March 2016. Therefore I am eligible to apply for the British passport in March 2021. I understand that I am allowed out of the UK for up to 2 years and have to make a landing before the 2 years is up. Can I be out for 2 years running? I keep reading I'm not allowed out of the UK for more than 90 days or 450 days in the 5 years so I'm confused. Can anyone please explain?
I've been out of the UK since July 2018 until now so I'm worried I've jeopardized my future application for the passport.

I'm not allowed out of the UK for more than 90 days or 450 days in the 5 years so I'm confused. Can anyone please explain?

The absence limits for British citizenship are no more than 450 days in the WHOLE 5 years immediately preceding date of application and no more than 90 days absence in the 12 months immediately preceding date of application. So you have been absent for 5 years, you don't qualify for citizenship.