Both taxes and benefits will incentivise behaviour. Judging by these threads, the current system is not working as well as it should for many people and is causing unwanted behaviours.
My suggestion is a fairly simple change - the benefits system needs to incentivise work so rather than a benefit that judges people on their mobility, it should be based on capacity to work (including working from home).
My own situation is that I am claiming PIP for mobility, but the fact is I can work from my bed. I have an adapted computer screen that I paid for that enables me to do so more easily.
My suggestion is that instead of PIP benefit payments, those that can work (but maybe need help funding whatever facilitates work) should be given extra tax allowances so they can earn more before paying tax. That would give disabled people an incentive to work and earn more, but at the same time they would have more tax-free cash to facilitate that work. In theory it would not cost the Treasury anything, swapping benefits for tax relief, but may encourage more people into work.
I am aware that finding work is hard, but that is a completely different issue and something else that needs to be tackled by Government generally.
I know many disabled people living productive lives. They don't really want hand-outs but a tax relief would be great.