HttpGet or HttpPost when paginating or filtering many parameters webapi2

I am working an a legacy ASP.NET webApi 2 (.net 461) and I have added refit to make make life easier.

Now There lots of calls where we are fetching data (GET) but we have many parameters as request. Basically something like below is a typical pattern with a search object that has 10-15 properties.

    [HttpGet] or [HttpPost]
    [Route("stuff")]
    [ResponseType(typeof(SearchStuffResponse))]
    public IHttpActionResult SearchStuff(SearchStuffRequest request)

Now what is the guidelines in this scenario

• HttpPost but we are fetching data
• HttpGet with a fromBody but seems wrong

Any suggestions?

Updated Simplified question