Bad RAM used while transferring large quantity of files, how bad is it ?

Sooo. I'm asking the question because i didn't find any definitive answer. Probably nobody can answer this but i just want to know if i'm in the shits.

So i build my data server (synology) one month ago. Transfered most of my files from multiple drives and external media to it. But i used my main computer to do the transfers.

I just found out that one my RAM of my stick was faulty after multiple crashes. Let's say 1000s of errors in MemTest kind of faulty. Replaced and tested everything, now it's fine.

But my question is... since i don't know when my RAM started getting faulty, did i corrupt most of my files i transfered using this RAM ?

I checked hundred of files, videos, etc... on my server, they seems fine. I rewrote a lot of them with some backup to check if they are the same. They are, at least the ones i had a backup for.

Sooo who i can be sure that most of my files aren't secretly corrupted ? I guess the videos, it would probably be a few frames that are out, so i wouldn't see it...

Thanks in advance,

And sorry if it is very noobish. But yeah i should have run Memtest before transferring so many TB of files...

edit : small corrections