Forlax can be combined with fiber, but it is worth bearing in mind that in the case of diverticula, soluble fiber is recommended.
Perhaps in the first place, it is worth increasing the supply of foods rich in soluble fiber, such as cereals (oats, barley), flaxseed, apricots, dates, figs, plums, apples and pears. If this effect is not sufficient, only then should supplementation be considered.

Here you can compare the prices of soluble fibre preparations and place an order with home delivery or collection at the pharmacy:

https://www.gdziepolek.pl/produkty/29714/fibraxine-proszek-do-wytworzenia-zawiesiny/apteki

https://www.gdziepolek.pl/produkty/19336/colon-c-proszek-do-wytworzenia-zawiesiny/apteki

In cities such as Warsaw, Wrocław, Katowice, Kraków, Lublin, Gdańsk, Łódź, Szczecin, Białystok, Poznań and Chorzów, products can be ordered with instant delivery in as little as 1 hour thanks to the Wolt Drive service.

- check if the service is available in your location: https://www.gdziepolek.pl/koszyk/szybka-dostawa?src=zf

I also attach links to helpful entries:

https://www.gdziepolek.pl/artykuly/3-kroki-do-zdrowych-jelit

https://www.gdziepolek.pl/kategorie/zespol-jelita-drazliwego-ibs