As stated above other items may be involved.
Plugins or free models may insert a script into your place somewhere you may not even expect. It might get hidden inside Lighting or one of the other folders/services in your Explorer window.
First off try turning off all your plugins, especially ones that you’ve recently started using.
Start Studio again with another fresh baseplate and try it out. If it gets better then it’s probably a plugin problem.
I had a similar issue last year, but my computer was 8 years old at the time and the hard drive was starting to fail causing everything to slow down. Since Studio was what I mostly use on my computer it was the first place I noticed issues.
edit
When you say you ‘imported’ a blank baseplate, was it the default baseplate from Studio, or one from free models?