This was quite difficult to calculate. I make it that our streak is 31, beginning with the 2019 R19 defeat of Collingwood (prior to that we'd lost two in a row against them). I can see how your method works - start with a clean slate after the 2019 R2 loss to Collingwood. However the following game we lost to GWS which made it consecutive losses to them, so using this method we're on 33, and will be on 39 after the next six "gimmes".
Using my method, if we beat GWS and Brisbane in Round 9 & 10, the streak will continue up to (at least) the start of the finals where it will be at 51.
Club record is 42 from 1931-33, followed by 32 in 1972-73. Losing to Carlton in the 1973 Qualifying Final cost us a streak of 47.
Best for each club:
81 Carlton 1906-10
70 Collingwood 1927-30
58 Essendon 1949-52
49 Port Adelaide 2003-05
42 Richmond 1931-33
41 Geelong 1951-53
40 Hawthorn 1975-76
36 Melbourne 1955-57, Fitzroy 1898-1900
34 Sydney 1935-36
27 West Coast 1992-93
23 St Kilda 2010-11
22 Brisbane 2002-03
21 North Melbourne 1977
18 Adelaide (first 18 games)
15 Fremantle (first 15 games)
14 Western Bulldogs 1955
12 GWS (first 12 games)
11 Gold Coast (first 11 games)
9 University (first 9 games)