Can't edit theme files outside built-in opencart theme editor

Hello, this is my very first time posting on forums for help so don't judge too harsh.

I have a project to add some data to checkout and thankyou page for marketing purposes (like order id, product id etc)
I did such thing before on the same site, but the client tried to change the theme and everything I wrote in View and Controller was reseted so I wanted to do the same again, but now there are some problems.

For example, I tried to edit checkout/cart.twig file to add 'product id' for each product to the page. Last time I just added 'product_id' to the variable just used it in cart.twig and it worked fine, but now it's not changing anything.
I disabled cacheing and activated debug mode, so it is not a cache problem, also, when I try to edit theme files directly from admin panel with the theme editor the changes are updated on the site, but I still can't acces my 'product_id' stored in from controller, it's just a blank value everytime. I tried to give a constant string to 'product_id' to see if data is even sent to View but it still was blank.

What may be the problem I can't edit .twig files directly without using opencart admin panel but rather from cpanel.

I have installed version of opencart V 3.0.3.2 with 2 installed themes the default one and UltraStore OCTemplates. They both seem to be activated.Maybe it's the problem, I don't have much experience working with opencart.

djmitry wrote: ↑

Thu Dec 03, 2020 6:51 am

.. but the client ..

Looks like a paid job.
And now you are asking here for free help?
Better post in the OpenCartCommercial Section

djmitry wrote: ↑

Thu Dec 03, 2020 6:51 am

the client

djmitry wrote: ↑

Thu Dec 03, 2020 6:51 am

I don't have much experience working with opencart

Why are you charging for your OpenCart expertise if you don't have any?

But as above, you'll have to either hope someone tells you how to do it here for free, learn how to do it, pay someone to do it, or tell the client to find another developer.