Frame and Fork compatibility - 1 1/4" to 1 1/2"
While there are options for mounting a smaller fork in a larger headtube, they're rare, weird and expensive.

For the opposite - The only way to mount a larger fork steerer in a smaller head tube is swap frame or fork, or replace the steerer on the fork.  Either will have costs.

Sounds like you need to find a fork that will fit your frame. Sorry.