On land while riding a Strider it becomes unaffected by the speed effect.
Also the speed effect barely has an effect on the strider while it is on land.
Further experimentation also shows that the levitation effect doesn't work on the strider while riding.
Thank you for your report!
We're actually already tracking this issue in MC-121788, so I resolved and linked this ticket as a duplicate.
If you would like to add a vote and any extra information to the main ticket it would be appreciated.
If you haven't already, you might like to make use of the search feature in the future to see if the issue has already been reported.
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