There's quite a lot to unpack there, and I'm no where near qualified enough to comment on some aspects. If you feel your lack of motivation is anything to do with depression or a wider problem please seek help won't you.
I can talk more about the numbers and work environment. My workplace has deteriorated over the last four years, I've found work hard, don't enjoy it as I used to, I've been at the same place over 20 years, and I'm taking my pursuit of FIRE extremely seriously.
I don't know if you've ever used the "where do I fit in" site of The Institute for Fiscal Studies?
https://ifs.org.uk/tools_and_resources/where_do_you_fit_inI'm not saying this in anyway to make you feel guilty or anything, but your household income puts you above 98% of households in the UK. You both have a very special opportunity to leave work early in one form or another. I would strongly recommend taking advantage of it if your health permits. Sometimes reframing a situation can help with motivation, especially when you can see a plan starting to come together, not wishing to sound like I'm in the A Team. If you can visualise the escape then I have found that has helped me in the work environment. I've set my own goals there. I've focused more on being a helpful as possible to other colleagues, not chasing promotions, not getting involved with any corporate fluff and nonsense, and trying to generate a many laughs as possible during the working day. It all helps.
Numbers wise don't worry about the pension access age of 57/58. Assuming you are going to be alive after this age (I do hope so) then the pension forms a vital part of the plan. It's long, but please read the Monevator series in order that I linked to. It's really very good.