Time Machine External Disk very slow on Mac OS Ventura (SSD External disk slow after Mac OS Update)

 Suddenly, my external SSD Time Machine becomes very slow after one Ventura Update. I tried everything. Default format: APS format, encrypted. 

I connected it and Finder took long time to read it, looks like hung for several minutes.

Had to use Finder, right-click on my backup drive name, choose "Decrypt"... this may take several hours/days. My 500GB SSD with 80% space occupied, tooks 3 days (connecting the disk 8 hours a day, I didn't want to keep it working overnight because it turns hot without. After that, Time Machine didn't accept my disk because "previous specified disk was encrypted, and current disk is not", so I removed from Time Machine and added again. Works very fast.

But I don't want a backup disk unencrypted so I use Finder, right-click on my backup disk and use the "Encrypt" option (this requires to specify a secure password, can't forget). Process begins and it looks almost 3 days (at eight hours a day) to encrypt. Finally, Time Machine again didn't accept my disk (because encrypted) so I removed from Time Machine, added again, and now, AT LAST, connecting my external SSD will not hangs Finder and backups now runs very faster. Also Finder is now responsive just after connecting disk.

MacBook Pro M1 now with Ventura 13.3.1