EDIT:: ANSWER AT BOTTOM
I have implemented: router.replace('/new-page', undefined, {scroll: false}) for a param query. The query works but the page scrolls to the top. How can this be avoided? Here is more code just in case:

export function ProductSort() {
  console.log("ProductSort rendering");
  const router = useRouter();
  console.log("Router:", router);
  return (
    <div className="flex items-center">
      <Select onValueChange={value => router.replace(value, undefined, {scroll: false})}>
        <SelectTrigger className="sm:w-[180px]">
etc etc etc

Any help appreciated. Thank you
ANSWER:
EDIT::: TO answer my question, the solution was:
<Select onValueChange={value => router.replace(${value}#store, undefined, {scroll: false})}>