Help please what is roughly % of Total Fixed Salary cost that is defined and allocated to Budget for Benefits

Ignoring for a moment the Taxes/NICs that add to the overall costs.
In simple terms I'm looking at an easy way to put into context how to break down our additional HR costs and budget requirements against a pre-existing cost - Salary.

I'm looking at the Benefit budget (is 10% a reasonable figure). This seperate from any incentive related rewards (bonuses, equity, etc.)

Where the Benefits budget would be going are into things like:
- 3% employer Pension contribution to factor in... but I am looking at meeting the 'Living Employer' criteria for Pension
- like to also account for adding PMI (which we are introducing next FY)
- looking then at cost of uplifting Paid Holiday Leave to 28 (currently 23-25)
- Introduce Employee Discount/Voucher scheme
- additional Salary Exchange options (EV, Bike, Nursery)

I know that Recognition % budget is recommended at:
- 3% - Best Practice
- 2% - 65th percentile
- 1% - 35th percentile