Good afternoon, how to modify the filter on records of arbitrary fields?

Question

WordPress

Good afternoon, there is a filter described in the article, a link to which I will attach below this wordpress post filter is absolutely working, but the problem is that it displays information only after it is applied, but it is necessary that all posts be displayed on the page before the filter is applied, and then already filtered out on the same page that is, supposedly the cycle was updated? tell me how to improve it? and plus another drawback is that the result of the filter displays on a different page, that is, the one to which the post request is sent, but it needs to be the same page where the filter form is placed

link to the filter code https://sebweo.com/ru/kak- dobavit-filtratsiyu-post...