The Cardano blockchain is more than 16GB in size as of October 2021, and it is predicted here that a full sync should take about 6 hours if you have a relatively good machine by recent standards (your 8GB of RAM may now be considered to be slightly on the lower end) and a broadband connection (I'm assuming you do). So it may be a bit of a surprise that it's only 89.6% complete after almost 24 hours.
These are some of the reasons why it might be taking you much longer than usual. First, Daedalus Mainset
is only consuming 64.5% out of the 98% CPU usage that you display in that screenshot, so something else is consuming (or trying to consume!) a significant amount of your CPU too, and when overall CPU usage gets that high, things can slow down considerably because the computer has to "ration" its resources.
The next thing is your RAM usage, from which things are not easy to tell. 8GB of RAM is very often not enough these days, depending on what else you have running on your computer (evidently there's more than just Daedalus Mainset
because that's only using 68% of your CPU usage, whereas your overall CPU usage is at 98%). Even though you're only using 49% of your RAM, it appears to be almost all by Daedalus Mainset
, and this suggests that it might have been possible that you ran into RAM issues (close to 100% usage) earlier, which caused paging (a process in which data that is intended to be stored in RAM gets transferred to disk to act as "virtual memory", which can slow down I/O enormously (this StackOverflow answer says it can be 100,000 times slower!).
Finally, you point out that you have 186GB free on your drive, which I don't think plays much of a role here since the Cardano blockchain is not even 20GB in size. You have plenty more space available than you need for this task, and also your disk usage is listed in your screenshot as only being 4% of your machine's capacity.
The problem may also simply be your slow internet connection, since the 100 Kbps displayed in your screenshot, would require about 41 years just to download a 16GB blockchain. I'm sure your network speed is faster from time to time, but if it's going down to 100 Kbps for long enough of a stretch of time, this could easily cause your lengthy syncing process.