No it’s not. Your previous thread “Installation Error - Failure reading sector from 'hd1'” already showed problems with your HDD, and given the age of your machine, it’s not unlikely that the drive is starting to become unreliable.
No. Your filesystem is damaged, and this may just be filesystem damage — which is what those commands I gave you should remedy, if possible — but given how robust btrfs is, and given your previous HDD problems, the probability of your problems being caused by your drive itself is becoming sufficiently convincing.
That’s a much more complicated question to answer than it seems.
First of and foremost, Manjaro is not a suitable distribution for just about everyone, regardless of how it has been promoted in the past. I’ve even written a short essay about it. 
The above in mind, Manjaro has been promoted as a distribution suitable for absolute beginners with no knowledge and/or understanding of GNU/Linux whatsoever. It’s a fact, and the community has come to accept that this misguided profiling of our beloved distribution has brought a number of absolute newbies to this forum. As such, we try to help and educate them as best we can.
But, as of Manjaro 25.0.0 Zetar, it was decided to make btrfs the default filesystem, which does not mean in any way, shape or form that one cannot opt for a different filesystem and/or a different partitioning layout at installation time. But unfortunately, newbies tend to stick to the defaults, and so now there are many newbies on this forum who’ve only recently installed Manjaro and who now have btrfs as their filesystem.
So far so good, because btrfs is a very modern yet tried-and-tested filesystem. It’s robust, and it’s powerful. And in my personal opinion, it’s more resilient than ext4. But, just as with Manjaro itself, btrfs requires periodic maintenance. It is not a filesystem for people who don’t know what they’re doing.
So, long story short, while I personally like btrfs — and I am using it myself, with a setup far more complex than anyone else’s here, and which most people here don’t even understand, let alone that they would be doing it the same way as I did — and while there is also a logic as to why Manjaro 25 uses btrfs by default — namely that btrfs is also the filesystem for Manjaro Summit, the immutable branch — I think that, given the amount of complete newbies in this community, the move to btrfs as the default filesystem may have been premature.
So, if you were to decide to reinstall, then I would advise you to choose ext4 and create separate partitions for / and /home, with a large enough swap partition alongside, given that your machine only has 4 GiB of RAM.
But then again, from where I’m sitting, looking at your previous thread and now this one, the matter is most likely academic — or at least, for remedying your current problem — because you’re almost certainly looking at a hardware failure, and no choice of a different filesystem is going to save you from the inevitable.
I’m sorry to be the harbinger of bad news, but I prefer being honest and transparent. I don’t like having to lie to people. 