Opencart Developer to help complete site upgrade OC3 to OC4

I need a talented and experienced Opencart developer to help me upgrade an opencart site from Opencart Version 3.0.3.8 to Opencart Version 4.0.2.2 Both sites run Journal 3 theme. I have 2 development sites, one is on OC3 and is a replica of the current live site (all works fine) and the other is OC4. With another developer who is no longer able to do the work I have got OC4 setup working but there are still some bugs that need fixing. The site sells digital products and runs a few simple custom extensions that need upgrading on the OC4 site. Paypal is working on this site already using Paypal OC4 extension (tested with sandbox so far) Extensions that need fixing for Opencart 4 (they are on the opencart 3 site working fine) Extension for stripe payments Extension for alipay payments Extension for wechat payments License upgrade module - This needs updating as it was meant to be updated but has not been. To summarise the module. The digital products have license options. Personal, business, commercial set at different price points. If a customer has already bought the private license for a product they may want to use it for business so would buy the business license, this module deducts the cost of the order they made already so upgrade cost is New Upgrade License Cost MINUS Personal License Cost = Upgrade cost. You can check the functionality on the OC3 dev site. One issue that also needs fixing on this is When someones order is denied, the next time they try to pay for it, it gives them the product for free. This needs sorting so if order is denied then they get no discount as they didnt actually buy the product but the module thinks they did. VAT validation number checker - This OC3 extension is not working (the store runs an euviess vat number validator). It doesnt seem to work correctly on this OC4 version but works fine on OC3 site. Bugs that I know of : Checkout payment methods not loading reliably, ajax just spins sometimes, I have seen a warning about Paypal issue (maybe sandbox issue) but its working currently so Im not sure the cause. Cart currently redirects to checkout (because with digital products we dont want QTY >1) but they qty picker in the checkout seems to have an issue, the ajax doesnt always reload it to show new qty) Download files are not showing even though the database has them showing and I made a dummy download file for the dev site (this works before) but nothing is showing in user control panel. Payment method bullet points in cart need formatting to be darker as they are white. Asterisk needs moving a little on product page options (license options) mobile site - checkout spreads of the screen a bit. (Journal 3 checkout) Register form has been customised to replace the register form extension used on OC3 site, just some fields removed, this seems to work ok. I have had to change a few extensions as they did not offer OC4 versions, Bulli quick product editor, and an abandoned cart extension. The new opencart 4 extensions installed are not quite as nice so if possible I would prefer to fix the current OC3 extensions, if not we use the new ones. Once the site is completed and I have tested it fully for bugs and we fix any issues found, there will be a second job which is helping me upgrade the customers LIVE site (which is the same as the OC3 development site) to the latest version of OC4. Here I will put the live store in maintenance(then we have to manually update the dev database with some table data from the live OC3 database (for orders, products,customers,download files etc) , import new images from live site (where they have added more products or blog posts) and once all tested working on the OC4 dev server we copy the files and final database from OC4 to live . I will do the unix server admin work needed, the download files are 2Tb but they remain on the server all the time and for testing I just use one dummy download file on the dev site. I have upgraded this store before so know what is needed. I need someone who has done Opencart 3 > 4 upgrades before and is very confident in their ability to fix any bug and upgrade any extension from OC3 to OC 4 compatibility. You also MUST know Journal theme. This is only a project for experienced opencart developers. I only want someone with attention to details who can work WITH me to find issues and then fix them. Please quote "ireaddit" to show you read the details on this project. You need to be a good communicator who does not disappear for days , must use sky pe or a messenger like slack for project comms ideally. I would suggest to quote for 10 hours work and then we will know exactly what we have to do from there to finish the job and can do another milestone. Same thing for the going live phase, we can estimate time to do it and any extra time that we didnt expect due to an issue we find when doing the go live phase I will add to the milestone. Thanks