woocomrce store design ( dont bid before read )

i have my own store and it's ready products installed and all integration is ready
but i want to
1- add mega category view and following categories IDs and brand category .
2-some editing to to avoid error checkout page .
3- place order with or without username .
4-do optimization speed . right now 24 second fully load with wp roket and cloudflare ready installed .
5- show full product name by customize font .
i have Astra them pro .
my store www.europharmacystore.com
Also make full screen view