example.html.erb

<div id="categories" data-controller="persist-scroll-position" data-action="scroll->persist-scroll-position#persist:passive" class="flex-auto flex flex-col gap-4 overflow-y-auto">
...
</div>

persist_scroll_position_controller.js

import { Controller } from "@hotwired/stimulus"

export default class extends Controller {
  connect() {
    this.element.scrollTop = this.position || 0
  }

  persist() {
    this.position = this.element.scrollTop
  }

  get storeId() {
    return `persisted-scroll-position-${this.element.id}`
  }

  set position(currentPosition) {
    localStorage.setItem(this.storeId, currentPosition);
  }

  get position() {
    return localStorage.getItem(this.storeId);
  }
}