If you have PMF, everyone staying behind is taking full market salaries and your valuation is based on a priced round then you should likely keep all your vested equity undiluted.

However, I assume that, as a pivot implies, you are pre-product market fit. In which case here are some questions to consider.

What is the value of the company after the pivot? How much of what was done pre-pivot has any relevance to the post-pivot company?

Is the startup valued at $20m or do you have SAFEs with a $20m cap? If the company is _worth_ $20m that means you've probably had a priced round and someone would likely pay $2m for your vested equity. Is that correct? Sell to them with a substantial, say ~50%, liquidity preference that goes to the Company (likely the Board's approval is required for a share transfer).

In large part the purpose of the SAFE is to avoid valuing the company. What valuation did you put on your 409A? Are you equating your "given a win-state valuation" (the cap) with your actual valuation (409A).

There is a Michael Seibel video where he talks about founder equity. In it he suggests that you should give back a lot of equity if pre product market fit as this will actually maximize your total return.

Remember if you raised $2m at $20m cap but have spent $1m your remaining co-founder is essentially taking $1m at $5m cap if compared to starting again (since they still have to hand over 10% to the investors and now they have to hand over 10% to you too but you spent $1m so they are giving up 20% for $1m).

Would it be more sensible for your co-founders to start a new company and offer the investors a substantial chunk or all of their remaining money back or to come with? Did they invest in them, you or both of you? In a liquidation how much would you get?

I would suggest that you should look to offer at least 90% of your vested equity to not have the remaining equity diluted. A good rule of thumb here would be what could you sell the company for today with no one staying (more than the a few months for minimal hand over) and divide the amount you raised by this number and this is the dilution you should be looking for.