Custom build of Openwrt for TL-MR3220 V2 with 8MB/64MB upgraded Memory

My current situation:
I have been using OpenWrt since 2015 on TL-MR3220 V2 with 4/32MB memory. It was running great. Recently, after buying a MI 4A gigabit router I stoped using the TP-Link router. With Mi router, I was able to add USB storage for a mini nas type solution. But last month I managed to fry the USB port of the Mi router. Now it can't access USB storage.

After that incident, few days have gone by and I had an idea to use my old tl-mr3220 V2 for network storage as it has a USB port and runs OpenWrt. But quickly I found out that I cant install the USB storage package because of the limited 4/32MB memory. So I searched for solutions and found that I can change the flash and ram chip. So I bought a new 8MB flash and 64MB ram chip. Flashed the new 8MB chip with the old 4MB chip dump using ch341a programmer. The router started successfully but the wireless was not working and I couldn't connect to the Internet with the router. As a result, I could not download the kmod USB storage package.

So I kept searching for solutions and found this solution. This worked. But the router became extremely unreliable to the point where it is not useable for anything.

My Questions:

  1. Is there anything I have done wrong or I didn't do or i should have done to make the router reliable?
  2. Is there any other easy way to do this?

If, there is no other way, as the last option I'll attempt to make a custom OpenWrt build. But, I think, that will be very hard for me as I have never done anything like that and don't know how it works.

Sorry for the mistakes. If you can't understand something please ask me.