It’s only 20% faster. You can try a reset and set up as new approach. Seems to fix most issues. The battery on your series 5 could also be causing slowdowns.
Not having that issue on my Series 4. I would remove unused installed applications from watch, stop running apps, and then do a watch shut down/ restart. If that doesn't work, a full reset might work
The battery seems to be OK. Battery Health is 86%. BTW, by next fall battery health might be below 80%. At that point I may take advantage of the battery replacement program.