We have set up a test site on our multisite here hidden link
And we are finding the results of the ajax search very slow to load.
The site is built on Beaver Builder but we are only using Toolset and addons for this project. We have no other significant plugins other than Ubermenu. We are hosted by Flywheel and currently on PHP7.1 As per Flywheel we use no caching plugins. We only have three CPTS to be called in the search.
For us, there is at least a 2-second delay before the initial search is completed and results are shown. After the initial search, it is much quicker. We are surprised at this delay as there are only 3 items to check and this concerns us as to what the delay will be like when we have hundreds.