I'm not familiar with your assertion that there will only be 2 workers for every pensioner... and that would depend if these are workers are net contributors or not surely? so what if we have more workers per pensioner if these are low paid workers, claiming more in benefits than they earn?
Raising the SPA affects the poor far more, they don't benefit from triple lock for very long, unlike the wealthier pensioner, so in the first instance, i'd impose NI on pension incomes, above a certain amount, reaching a certain age, shouldn't mean a tax cut.
There also needs to be higher contributions made on working people & business now, the levels currently are far too low.
I'd also have a state insurance scheme for social care, everyone pays in, inc employers, ring fenced, this would reduce the benefits bill as well.
Changes to IHT, more bands, 10% 20% 40%... get rid of trusts, the wealthy should not be able to protect their wealth if the poor cannot not.
Triple lock reductions or cuts in SP ? mean higher benefits for poorer pensioners..
Raising the SPA affects the poor once again, the wealthy tend not to do physically demanding jobs, so can, if they wish, work for longer and/or retire earlier.
Where as those doing tough jobs will have to leave work and live in poverty on benefits.... doubtless dying even younger than before... Great!!!
All your solutions hit the poor, a means tested pension wont affect the rich but it will hit the less well off just above any threshold - see cuts to WFA !