The partitioning looks fine to me. I don’t believe that would cause things to run slowly even if it were incorrect. That is something that either works or it does not.
There are (many) other possibilities. Since you appear to have an ATA disk drive, maybe this one?
~~ Extremely slow disk access - #8 by computersavvy ~~
Nevermind, I read the wrong line from your last post. I see you said it is an SSD. In that case, maybe it is this “discard storm” problem that has been mentioned recently?