Woocommerce Eshop - Fine tune caching layers Object Cache, Redis, Varnish, Cloudflare, Breeze

We have observed a pattern of weird behaviors on our ecommerce site when we have caching layers on which gives us a speedy website but is causing lot’s of other problems at the same time. Epigrammatically, when we have caching layers ON, the following anomalies occur: 1. Products get zero price by themselves (0) at random - In the list view it shows a zero price - When you edit them, they have the normal correct price - The customer can buy them with a zero price. 2. Products get an irrelevant price by themselves at random - In the list view it shows a changed price - When you edit them, they have the normal correct price - The customer can buy them with the wrong price. 3. Products take themselves out of the categories they belong to - When you edit them, they are in the correct category - This creates other problems to other plugins such as assigning points to products when they shouldn't. 4. We have a system that gives some free products (Free Gifts for Woocommerce) which are automatically added to the customer's cart if they meet the criteria, but in many cases they are not included when they should be. 5. We have a points system (yith points & rewards) in which we have set some categories not to give points such as the free gift products, but many times the opposite happens. 6. We have in some cases duplicate, triplicate and even quadruple orders, from the same customer, exactly the same products, same prices, same charge. - This is problematic because an order can be accidentally fullfilled multiple times. 7. We have in some cases the same order, with the same ID displaying two times on the list view on woo backeend. 8. In some failed card orders where the customer returned to pay again and selected cash on delivery from the list of available payment methods, their order went through but the cash on delivery fee was not charged. 9. Customers try to apply points earned from their purchases to get a discount on their order, but the system does not accept it. 10. In some cases, the accounting department makes some additions and removals manually to points in the backend for our customers, sometimes the list does not show that the addition or removal was done, it is usually solved with a clean cache from wp rocket / breeze. After a lot of troubleshooting, research in forums, wp / woo communities, colleagues, support tickets, etc. we have come to the conclusion that caching in general is probably to blame and so to avoid these anomalies (we had cloudflare enterprise + wp rocket + varnish enabled) we had to disable all of them, the site is slower but a bit more stable, but we still have occasional problems of this type even with caching off. Essentially we have turned off all caching layers to mitigate these anomalies, which occur from time to time but a lot less frequently. Our server is in cloudways. Their support could never provide us with any solution to our problems. We want to have the caching layers ON because they help a lot in speed, user experience and SEO and in keeping the server's resources balanced, but at the same time we have these anomalies and that's why we want to solve it once and for all. Also, all these problems cannot be recreated on demand (unless simulated somehow), they happen by themselves randomly. We would like your help as an expert and skilled dev to identify what is wrong and to fine tune our eshop and its Plugins to play nice with all the caching layers we can have, so that we achieve optimization + speed + stability. It is also wise to do a general check of the site as well as a check of the database to see if its integrity has possibly been affected and if possible to declutter it and optimize it, remove junk entries. The site has recently been updated in everything (wp, woo, themes, plugins). Attention: We have some customizations in Plugins, so if an update needs to be done, we should first consult our documentation where we keep a detailed record of which plugins can be updated and which cannot and proceed accordingly after approval. Definitely do not update to the following plugin: WooCommerce PDF Invoices & Packing Slips I am at your disposal to provide you with any information, insight, access and contact with the devs of the Plugins we have issues with as well as access to cloudways support so you can talk directly with them.