As far as I know (got divorced several years ago, reasonably high net worth):
It is fundamentally a negotiation around a rough idea of ‘fairness’ which both solicitors know. It is rare it goes to court as, if it goes through the full court process, it can cost 10s or even 100s of thousands.
If there is sufficient funds for you both to maintain your current lifestyles with assets, then you can start to discuss extra marital assets etc. But, if that is not the case, which is far more common, and the marriage has been long, generally the assets are split so both parties can continue with their current lifestyle as much as possible (normally both suffer a loss of lifestyle, at least at first).
Pensions aren’t just considered the same as cash. They are normally discounted, as there is thought to be a value in readily available funds. The closer you are to pension age, the closer they get to cash.
Ultimately, you need to think of what would be fair going forwards BUT be prepared to negotiate around it. Your STBXH should do the same. It is human nature that you will both err in your own favour in your idea of fairness, so be guided by your solicitor and ask them unloaded questions.
Unless there are many millions at stake, court is best avoided.