Its a tax on profits though. If a business is struggling it won't pay it anyway.
It is the definition of struggling - so the 25% rate begins to kick in from taxable profits (so a business can be loss making due to non taxable expenditure such as depreciation - big plant and machinery can do this quite easily) of £50,001 and marginal relief ends when profits are over £250k which would hit them quite hard.
A return to the previous marginal split of (if memory serves) £350,000 and £1.5m would be better I think.
Either way, the ones who benefit most are your multi million pounders - if you've made a £120m profit (which Sainsburys did in 2020 for example) then you have received 6% saving on that (the £250k is trivial so ignoring it for the calc) which is £7.2m of tax saved.
That isn't getting reinvested I can tell you that much. Most likely it will get paid to shareholders, directors etc by various means and as someone said on here recently they can only spend so much so most will be in savings or investments etc.
If they were to insist on lowering taxes then I think they should have dropped the small profits rate to 17% (in line with thier original plans before they moved to the 25% idea) and then had the large profits rate be 23% as that would then take pressure of businesses at the bottom end but still get a fair whack from bigger ones.