WordPress website changes and fixes

*** ONLY REPLIES starting with “MANUAL REPLY” will be considered ***

At website boatcareltdmalta.com we are looking for the following tasks to be completed:
1. Changing the filtering of the charters page at https://www.boatcareltdmalta.com/destination/rent-a-boat-in-malta/
2. Changing the filtering of the brokerage page at https://www.boatcareltdmalta.com/product-category/quality-pre-owned-yachts-for-sale/
3. Fixing of WordPress bug when someone adds an item to the cart
4. Updating the website for upgrade to PHP 8.0+ and WordPress 6.0+

Only experienced WordPress developers
Time = money therefore no time wasting
The developer has to provide code/db changes documenting the change/fix for all points above