That the pension system is different for those who retired pre 6 April 2016 and post this date has confused the hell out of a lot of us Shinamae, so you are in good company.
I'm not due to retire until I'm 67 - 8 years from now. At current rates the full pension that I would have received had I paid what is classed as full Nat Ins for post 6 April 2016 would have been £175.20, but although I've paid over 35 years Nat Ins, like some of other peeps who have posted for some years I was contracted out, and my current forecasted pension is around £35 per week less than this.
I do have the option of paying voluntuary NI contributions within a certain period but as Ive not worked since 2018 the current class 3 Nat Ins Voluntary Contribution rate of just under £800 per year are not affordable. Hubster on the other hand (retires at 66 in July 2023) is forecasted to get around £40 per week more than the current max 'new' state retirement pension, Neither of us is quite sure how he's managed that one.
If someone is of retirement age and their income is less than the pension credit amount (currently £173.75 (for single people) or £265.20 (for couples), they may be able to claim a pension credit (which is means tested) to top their income up to these amounts (plus I think - though am no longer 100% sure - that being in receipt of pension credit also gives a 100% help with Council Tax Benefit and some help with Housing Benefit (if renting a property). See the link below for more information
www.gov.uk/pension-credit
With you working at the current time Shinamae, its unlikely that you would be eligable to pension credit, though may be worth bearing in mind for the future. Though like anything to do with pensions and/or benefits, this might be subject to future changes by the Government.