The scan times you are seeing does not sound normal. Even though the speed of the HDD is what is most important, not the CPU and RAM. What harddrive is it?
Where did you install Strawberry from? Are you running it as a snap, from PPA or from the regular releases? What audio files do you have? Do you have CUE sheets?
I compared clementine vs strawberry here using a stopwatch, and this is the result:
My collection has 26610 files including music and album covers in almost all album directories, mostly FLAC, but a few MP4, no CUE sheets. It is stored on a KINGSTON SA400S3 SSD 900GB. The HDD only have 200GB of space left which might or might not decrease the speed of the HDD.
I used the latest code of Clementine from source compiled with Qt 5.15.1.
I used the latest code of Strawberry from source compiled with the latest source of Qt 6 from the dev branch.
I use openSUSE thumbleweed.
First I rebooted the computer so any caching on the HDD is cleared. Then I added my music folder to Clementine, the scan was done in 9 minutes and 41 seconds.
Then I rebooted the computer (so the caching is cleared) and did the same with Strawberry, it was done in 9 minutes and 50 seconds, so only circa 10 seconds difference, but that's probably coincidental, ie other things on the computer going on, etc.
I have not tested on a regular mechanical drive, only SSD, the speed would be significantly slower on a regular HDD.
When removing the music directory and re-adding it the scan is done in 20 seconds (because of HDD cache).