I used this list. Adds up to 40. Whether the list is correct is another matter.
Manager Start Date - End Date Record
Tommy Wright 19 Apr 2021 - Present Won: 2, Drawn: 0, Lost: 2
John Sheridan 13 Nov 2020 - 18 Apr 2021 Won: 8, Drawn: 4, Lost: 21
Noel Hunt 04 Nov 2020 - 13 Nov 2020 Won: 1, Drawn: 0, Lost: 2
Richie Wellens 13 Nov 2018 - 04 Nov 2020 Won: 35, Drawn: 17, Lost: 31
Phil Brown 12 Mar 2018 - 11 Nov 2018 Won: 10, Drawn: 11, Lost: 11
David Flitcroft 05 Jun 2017 - 01 Mar 2018 Won: 21, Drawn: 3, Lost: 18
Luke Williams 30 Dec 2015 - 05 May 2017 Won: 20, Drawn: 22, Lost: 33
Martin Ling 03 Nov 2015 - 29 Dec 2015 Won: 5, Drawn: 0, Lost: 4
Lee Power 18 Oct 2015 - 03 Nov 2015 Won: 0, Drawn: 1, Lost: 2
Mark Cooper 24 Jul 2013 - 17 Oct 2015 Won: 52, Drawn: 28, Lost: 45
Kevin MacDonald 01 Mar 2013 - 12 Jul 2013 Won: 4, Drawn: 5, Lost: 5
Fabrizio Piccareta 19 Feb 2013 - 01 Mar 2013 Won: 1, Drawn: 1, Lost: 1
Paolo Di Canio 20 May 2011 - 18 Feb 2013 Won: 54, Drawn: 18, Lost: 23
Paul Hart 03 Mar 2011 - 28 Apr 2011 Won: 1, Drawn: 4, Lost: 6
Danny Wilson 26 Dec 2008 - 02 Mar 2011 Won: 44, Drawn: 40, Lost: 37
David Byrne 14 Nov 2008 - 26 Dec 2008 Won: 1, Drawn: 4, Lost: 3
Maurice Malpas 15 Jan 2008 - 14 Nov 2008 Won: 13, Drawn: 11, Lost: 18
David Byrne 27 Nov 2007 - 15 Jan 2008 Won: 3, Drawn: 4, Lost: 3
Paul Sturrock 07 Nov 2006 - 27 Nov 2007 Won: 26, Drawn: 11, Lost: 15
Adrian Williams 24 Oct 2006 - 07 Nov 2006 Won: 0, Drawn: 0, Lost: 2
Dennis Wise 22 May 2006 - 24 Oct 2006 Won: 9, Drawn: 5, Lost: 3
Iffy Onuora 26 Sep 2005 - 22 May 2006 Won: 10, Drawn: 15, Lost: 15
Andy King 20 Dec 2001 - 26 Sep 2005 Won: 71, Drawn: 48, Lost: 75
Roy Evans 03 Aug 2001 - 20 Dec 2001 Won: 10, Drawn: 6, Lost: 10
Andy King 01 Nov 2000 - 31 Jul 2001 Won: 12, Drawn: 11, Lost: 14
Colin Todd 04 May 2000 - 01 Nov 2000 Won: 5, Drawn: 6, Lost: 9
Jimmy Quinn 02 Oct 1998 - 02 May 2000 Won: 19, Drawn: 21, Lost: 45
Steve McMahon 28 Nov 1994 - 23 Sep 1998 Won: 74, Drawn: 48, Lost: 79
John Gorman 04 Jun 1993 - 21 Nov 1994 Won: 14, Drawn: 20, Lost: 34
Glenn Hoddle 04 Apr 1991 - 04 Jun 1993 Won: 49, Drawn: 32, Lost: 34
Ossie Ardiles 19 Jul 1989 - 31 Mar 1991 Won: 38, Drawn: 33, Lost: 31
Lou Macari 23 Jul 1984 - 03 Jul 1989 Won: 132, Drawn: 63, Lost: 75
Ken Beamish 01 Mar 1983 - 30 Jun 1984 Won: 24, Drawn: 17, Lost: 28
John Trollope 01 Nov 1980 - 01 Mar 1983 Won: 45, Drawn: 36, Lost: 44
Bobby Smith 17 May 1978 - 31 Oct 1980 Won: 62, Drawn: 26, Lost: 46
Danny Williams 06 Mar 1974 - 01 May 1978 Won: 87, Drawn: 61, Lost: 78
Les Allen 10 Nov 1972 - 28 Feb 1974 Won: 13, Drawn: 20, Lost: 31
Dave Mackay 31 May 1971 - 01 Nov 1972 Won: 18, Drawn: 18, Lost: 25
Fred Ford 01 Oct 1969 - 31 May 1971 Won: 35, Drawn: 23, Lost: 25
Danny Williams 01 Aug 1965 - 01 Jul 1969 Won: 104, Drawn: 58, Lost: 60
12 different managers during my 11 years working for the club certainly fits with the kind of consistency you'd expect from STFC!