Advice on optimising savings and pension contributions

Hello all - as per title hoping to get some advice

29M single no kids, but potentially in the next 3-4 years. No ambitions for early retirement etc per se but am aiming for financial independence and to build resilience in case of redundancy / desire to change to a lower paying career path in the next 10+ years.
£170k base salary ~ £260k TC and expect ~5-10% growth from here on out for the next few years
~ £25k RSU vested over the next 3 years and generally speaking ~10-15% of annual bonuses are tied up in RSU/deferred cash over 3 years
Bought doer upper flat spring last year for ~£650k and depleted all savings on buying + refurbishing it. Estimated market value of the flat now gone up to ~£740k so around £180k equity in the flat. Currently live in the flat and no imminent plans to move but may look to upsize to a house in the next 5 years.
~ £23k in S&S ISA all currently in diversified global stock index.
£20k in savings account (expecting an upcoming lump sum cost for external flat refurb in the next 8 weeks) so prefer to keep this on hand for time being.
As my savings grow post this expense being paid aside from continuing to pay into ISA I’m thinking of parking any excess cash into high yield savings and maybe some blend of premium bonds. Don’t have particularly high conviction in the stock market at the moment so happy with the exposure I get via ISA/Pension
~£8k monthly net income (exc. bonus)
~£2.6k monthly mortgage
Other monthly expenses on average £2k
Workplace managed pension of £69k - I contribute 5% monthly + 12.5% top up from employer (this maxes out the employer contribution) + this year I contributed £25k from my pre-tax bonus
Point to flag is I moved back to the UK from abroad 3 years ago and didn’t have a pension in the UK at that point. As a result of under contributing into my pension over the past few tax years I have quite a bit of spare capacity to get up to the £60k annual allowance on a 3 year look back basis so one easy win I see is to over contribute into my pension to use this spare capacity and take advantage of the tax shield. Also conscious of hitting up to the taper threshold for pension so keen to use this while I can.

Question being is how does one go about using this capacity, is it as simple as ramping up my monthly pension contributions and declaring in my self assessment? As things stand I will be hitting my £60k pension contribution limit with my current set up by end of the fiscal year. Away from this any other advice on how I could optimise/do things differently would be highly appreciate