Nobody knows how many gurdwaras there are.
The SGPC manages a few hundred historic gurdwaras in Punjab, Himachal and Chandigarh under the 1925 Act. Haryana's are under the Haryana Sikh Gurdwara Management Committee, created by a state law of 2014 that the Supreme Court upheld in 2022. The Delhi committee manages Delhi's. Takht Sri Patna Sahib and Takht Sri Hazur Sahib are under their own state laws. Pakistan's are under the Evacuee Trust Property Board.
Beyond those, every village in Punjab has at least one and many have several, and none of those is centrally registered anywhere.
Abroad there are several hundred in the United Kingdom, several hundred in Canada, hundreds in the United States, and others across Europe, Africa, Asia and Australasia, each an independent charity under its local law.
Estimates of the worldwide total run into the tens of thousands and none is based on a count.
A religion with no central authority, no ordination and no registry has built tens of thousands of buildings, each funded by donation and run by an elected committee, and nobody has a list.
Nobody knows the number. Estimates for Britain run into the hundreds, for Canada and the United States similarly, and there is no register anywhere covering them all.
They are registered as charities or as religious societies under whatever the local law is, so the information sits in a dozen national systems and has never been collated.
A directory of the world's gurdwaras with founding dates would be a picture of Punjabi migration over a century, and it would take one person with a spreadsheet about a year.