Search within a string and return data

Hello,

I am wanting to search from within a string, search only when:

filter=(a_brand_t_fq:"BrandLoonry")

and return what's in the quote. so whenever you see: "filter=(a_brand_t_fq:" return the value in quotes so it should return, BrandLoonry

Original:

https://www.abc123.com/search?breadcrumbs%5B0%5D=red-big-widget&breadcrumbs%5B1%5D=red-long-big-widgets&cc=LUNERATOOBS&facet.multiselect=true&page=1&q=*&rows=15&son=0&sort=price+asc&start=0&filter=(category:"12897")&filter=(a_brand_t_fq:"BrandLoonry")&filter=(a_length_d_fq:[12%20TO%2024]%20OR%20a_length_d_fq:[24%20TO%2036]%20OR%20a_length_d_fq:[36%20TO%2048])&filter=(a_dimmable_t_fq:"Yes")'),

Desired: result.

BrandLoonry

See spreadsheet for actual data on 1st tab and desired result on 2nd tab.

thanks in advance