Crossed 250k net worth at 30 - but it's nearly all pension. Is FIRE by 50 realistic for me ?

Firstly this isn't a 'i have 15 billion can I maybe retire if I earn another ten billion a year for the next fifty years ?' post but I realise fire may be out of reach for me before a potentially very comfortable retirement. I am grateful for my position and not looking for humble brag reassurance or anything like that, just some ideas about different options going forward. I am aware that if I can't retire early but I do make retirement if I continue like this it would be very decent.

I'm 30, my networth is as follows:

-House worth about 435k (280k mortgage) shared with partner -20k VAFTGAG stocks and shares ISA (trying to add 500-750 a month) -30K cash (premium bond emergency fund and a 5.75% interest account). High cash as have been spending a bit doing up the house.

• defined benefit pension which will reach a value of 10k per year guaranteed value at the end of this year (I've calculated it's worth as about 200k based off 20 years x 10k as it's guaranteed from retirement age and linked to RPI). I'm adding over 1500 a year value to it as things stand.

Therefore whilst technically I'm over 250k networth it's predominantly stuck in a pension that I can't access til my late 60s, or if I do access it I'll take severe (but understandable) penalities and get a lot lower value.

I earn about 65k, I could and have turned down jobs earning more but I just really love my job and it's a job I would have dreamt of when I graduated so I'm really keen not to chase money as some better paying jobs I've done I've hated so I kept changing until I found what I loved. I have the potential to earn more but I'm not great at doing something I see no joy in so I won't rush for a higher pay for the sake of it.

I assumed by chucking about 750 a month away into VAFTGAG I'd be flying by 40 but even doing the maths I'll end up with maybe about 300-400k in my 50s. Obviously fantastic with my pension but hardly getting me out at 45 like I'd dreamed and much more late 50s/early 60s.

Needing some hard truths here - if I'm to fire by mid 50s I guess I need a job without the generous defined benefit pension but more cash or a few promotions? Lets assume my partner's income doesn't impact me other than paying half the mortgage and bills and zero inheritance.

Harsh truths welcome because as much as I like my job I like sitting in the garden with a coffee and nowhere to be even more !