ILR QUALIFICATION;in UK for 18 years and 3 months

I have been in UK for 18 years and 3 months.
History;
- Sept 2004 - July 2008; student visa
- 2008- 2010; PSW visa
- 2011- 2012; student visa
- 2012 - 2019 overstayed
Applied for FLR(FP) parent route 2019
- granted march 2020 - September 2022(10 years route) with Recourse to public funds.
Currently have application in now for Extension on FLR(FP) with 1 British child and 1 child due for British this year.

My question is, can I apply for ILR after spending overall 20 years in this country?

My question is, can I apply for ILR after spending overall 20 years in this country?

No. You need to wait till you have either 5 years in a qualifying visa or 10 years in any visa legal stay.

There is no 20 year ILR rule.