Multiple point releases of NT have received multiple service packs. SPs are absolutely not equivalent to or interchangeable with SPs.

For reference, these are the version numbers of NT:

3.1 -- 3 SPs

3.5 -- 3 SPs

3.51 -- 5 SPs

4 -- 6 SPs

5 (Branded "Windows 2000") -- 4 SPs

5.1 (Branded "Windows XP", "Server 2003") -- 4 SPs

6 (Branded "Windows Vista", "Server 2008") -- 2 SPs

6.1 (Branded "Windows 7", "Server 2008 R2") -- 1 SP

6.2 (Branded "Windows 8", "Server 2012")

6.3 (Branded "Windows 8.1" "Server 2012 R2")

10 (Branded "Windows 10", "Server 2016", "Server 2019", "Server 2022"); 10 numbered build releases issued, then 4 datecoded ones; 14 in all.

11 (Branded "Windows 11"); 2 datecoded releases so far.

In other words, 7 versions of NT with a minor-version point-release so far, and in total 16 service packs for those point-releases which did not change the major or minor version number.