An EU type agreement will keep peace for some time. Remove all trade barriers between two countries, have a treaty preventing any side to be used militarily by third party, no attacking each other and free movement of all vessels through each other's seas. Maybe few more
Thats just buying China more time until they can get their chip manufacturing to at least a similar ballpark. Then Taiwan has no cards left to play. China can cripple TSMC depriving the west of chips while they continue onwards.