Webflow extension development: data exchange trouble

Hi dear webflowers!

I’m trying to build a hybrid webflow extension which can paste customized multi-selects/dropdowns with options list. Options list should be received from API calls, I was planning to use CMS collections for that and that’s were the Webflow data client part steps in. In addition, upon selecting option from select/dropdown list – the result must interact with the rest of the data on the page. For example, if my select/dropdown contains filter options for some collection displayed near to it – this collection should be filtered according to the options I selected. And I’ve faced some problems and have questions.
1.First of all, I’ve tried a webflow hybrid example (GitHub - Webflow-Examples/Hybrid-App-Example) as a starting point, and tried to test Devflow image generator, and apparently the code in the example is a little bit behind the documentation. When we are making call to (${BACKEND_URL}/api/images?${params.toString()}) – the request goes well (200), but in response body we receive 401 – looks like auth token is lost somewhere, and I’m not quite sure where. Does anybody know what can be the reason?
2. Same thing with collections, so my idea was to receive a list of collections – then through extension’s interface user can choose which collection to connect with the select we paste. For data-client I made api/collections folder, which contains handlers to handle requests to the api endpoint (https://api.webflow.com/v2/sites/{site_id}/collections). In extension client we send a request to (*/api/collections) and it should return a list of collections. Except it does not, with the same 401 status. Just for example, I’ve tried to make request directly to the collections endpoint from extension client, just copying and pasting webflow_auth token directly in new Webflow constructor (hardcode, apparently) and it worked fine. However, if we send request as intended, through data-client – 401. I could use your advice on this one (or maybe more fresh working examples please)
3. Is it possible to design the extension without separating it into the data client and extension itself? So I could have api calls and visual interactions with the canvas in the same app?
4. I have noticed, that webflow only allows pasting selects into the forms, and actual data interaction (like filtering) between filters and lists goes through the forms (using finsweet for that). Is it possible to achieve same functionality with CMS collections with filter being outside of the form?
5. What if we paste and use "select> outside of the form (yeah, it allows me to, but will it be interacting with data as stand-alone element)?
6. Also, so far couldn’t figure – how to send a callback from my custom element and expose the end value of interaction (like we selected an ) to the rest of the canvas and webflow native elements?
7. Maybe you could give me any advice or guides (IF it’s possible at all) to inject your webflow-api, webflow-cli into the pure React or React/Typescript app (without initialing the app through webflow-cli, but adding it)?

I’ve reached out via the support@webflow.com email several days ago but haven’t heard anything back yet.

Here is the read-only link to our website, the section that we are working on is “open positions” at the home page.

Our clients wants this section to look approximately like this and we’ve been struggling with it since a month.

It’s also important in our case not to use the ready-made solution like Memberstack multiselect for example.

Thank you for your help guys and good luck in your Webflow projects!