Can I use Zephyr Strike outside of combat to increase my running speed?

The spell Zephyr Strike, from XGE, has the following text:

You move like the wind. Until the spell ends, your movement doesn’t provoke opportunity attacks. Once before the spell ends, you can give yourself advantage on one weapon attack roll on your turn. That attack deals an extra 1d8 force damage on a hit. Whether you hit or miss, your walking speed increases by 30 feet until the end of that turn.

Clearly this spell was written with combat in mind. I’m curious what support, if any, exists for using it outside of combat for the purpose of increasing a character’s movement speed, for instance in a foot chase.

What I would like to happen: I cast Zephyr Strike, waive the attack, and immediately trigger the bonus 30 feet of speed (say, to 60 ft). Since Zephyr Strike’s casting time is a bonus action, I then take the dash action, doubling my speed to 120 feet. I have this speed for 6 seconds.

My interpretation of the spell as written: The bonus to speed requires the player to take the attack action. The extra speed only lasts until the end of the turn. So to gain the speed benefit, a player must attack something, which uses their action and prevents the use of the dash action while under the effect of the spell.

Obviously the DM can rule however they want, but I’m curious what support the rules might have for my preferred outcome.