php expert needed for search result page query fixing

basically we are looking for 21 days generalize formula
we will do a formula which will pick dates from 1-21 days
with 3 offers
search result page
https://www.test.ischiahotel.net/index-nuova.php
------------------------------------- 5-12 june-----------------------
1. hotel villa svizzera 609 € but the price for this week in this hotel is 529+529
2.hotel onda blu also is wrong because the correct price is 269+269 not 690 €
3.gran paradiso also is wrong because you show 898 but the correct is 998
4. missed many hotels like hotel san giovanni, hotel eden park, hotel stella maris, they not show in your search
5.Stella Maris from 5 to 12 june cost 345€ per person
6.For San Giovanni we have 2 offer:
1) from 21/05 to 11/06
2) from 11/06 to 9/07 and in this case we have to mix the 2 prices
==============================5-19 june===========
Annabelle is ok
Onda blu is wrong (correct is 1076)
Gran paradiso is wrong (correct is 1996€)
===========5-26 june===========
1.Annabelle is wrong (correct is 1890€
2. Gran paradiso is wrong, correct is 2994
3 hotel onda blu is wrong, correct is 1614€