Vala is legit, I’ve bought several times from them.
It’s possible that you fried some diodes on that side of the board matrix, but it could also be that there’s still some moisture in there. Compressed air to the back of the PCB can make sure it’s dry.
It’s possible to get to the back of the board and replace the diodes if you are comfortable soldering. You can see the back of a K70 here: https://youtu.be/ZeIqMQ2WDaY?t=340
I’d maybe consider this an opportunity to get a more disassembly-friendly mech, though…
It’s the last day for Molly60, which has been getting really good reviews as a budget 60 if you wanted to try that:
Etsy has many, and you can pick one to match the exact dimensions of your keyboard including front height. I got this one, 32cm length, for a QK65, for example: https://www.etsy.com/listing/874420061/
If you can find a southpaw WindX, that might meet your requirements. Unfortunately only the right hand version seems to be in stock, so you would have to check aftermarket.