The only method I know of doing this is as follows and has one major problem: the search does not differentiate between surname and forename(s) and so would require some manual work (unless their is a way to limit results to surname only on WikiTree+)
1) Find out the total number of profiles with a surname of your choosing (e.g. 1793 for Maguire)
1B) You can do this by clicking Find<Search<Last Name "Maguire" from the top right of your screen
2) Open WikiTree+ and click on the the 'Search' menu then the 'Text Search' menu
3) Under the heading 'Text' put in your search parameters e.g.
Maguire - searches for those with the name Maguire
Connected - searches for connected profiles
Open - searches for open profiles (including those with Project Protection)
20cen - searches only for profiles with dates in the twentieth century
Of course, those values are just examples which can be substituted or left out as needed
4) Under the heading 'Max Profiles' take the total number of profiles with your desired surname and round upwards to the nearest 500 (e.g. Rounding 1793 to 2000 for Maguire)
5) Click the 'Get Profiles' button
Now, you will get a batch of results like: https://wikitree.sdms.si/default.htm?report=srch1&Query=Maguire+connected+open&MaxProfiles=2000&SortOrder=LNAB&PageSize=500