See: User:Timeshifter/Sandbox228

Copied this to here in order to test if it works without a wider table on the page.

Solution for single row header. Narrower table by itself

edit
Cumulative COVID-19 deaths. Jan 1, 2021
Date First case Jan 1
World 1,472,363
Days to double 112
Countries and territories 196
  USA March 3, 2020 335,789
  Brazil March 19, 2020 193,875
  India March 13, 2020 148,994
{{mw-datatable}}{{sticky header}}{{table alignment}}
{| class="wikitable sortable mw-datatable col1left col2left" style=text-align:right;
|+Cumulative COVID-19 deaths. Jan 1, 2021
|- class=sticky
!Date!!First case!!Jan 1
|- class="sorttop static-row-header"
|World || ||1,472,363
|- class="sorttop static-row-header"
|Days to double || ||112
|- class="sorttop static-row-header"
|Countries and territories || ||196
|-
|{{flag|USA}} ||{{Date table sorting|2020-3-3}} ||335,789
|-
|{{flag|Brazil}} ||{{Date table sorting|2020-3-19}} ||193,875
|-
|{{flag|India}} ||{{Date table sorting|2020-3-13}} ||148,994
|}

For portrait view on cell phones:

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